The following discussion summarizes the meaning of the "host (Hebrew = saba/tsaba) of heaven" ("army of the skies") (see related study on the Name of God, Jehovah Sabaoth) a term which can be somewhat confusing because of overlapping meanings as discussed below. For background you might first click and study the 18 uses of the phrase in the NASB.
Related Resource - Word Study on Tsaba = Hosts, Armies
Host of heaven has two basic meanings depending on the context…
1 Heavenly Bodies = stars - as created things and/or as objects of idolatry
2 Heavenly Beings = angels or spirit beings
The first Scriptural use of Host of Heaven is found in Deut 4:19
Deut 4:19 "And beware not to lift up your eyes to heaven and see the sun and the moon and the stars, all the host of heaven, and be drawn away and worship them and serve them (note the progressive decline in the preceding verbs), those which the LORD your God has allotted to all the peoples under the whole heaven."
Morris commenting on this passage writes that "The pagan nations of Canaan, as well as Egypt and the other nations of antiquity, had once known the true God of creation but had long since become evolutionary pantheists, worshipping the creation instead of the Creator (Ro 1:20-25- see notes Ro 1:20-21, 1:22-23, 1:24-25). The children of Israel were repeatedly warned against this influence but repeatedly succumbed to it in later years--just as have people in every age. The first of the ten commandments, "Thou shalt have no other gods before me" (Exodus 20:3) was given explicitly to guard against this ever-present Satanic temptation. (Morris, Henry: Defenders Study Bible. World Publishing)
Jeremiah records that despite God's clear warning not to worship the host of heaven they disobeyed "And the houses of Jerusalem and the houses of the kings of Judah will be defiled like the place Topheth, because of all the houses on whose rooftops (flat roofs of the houses were used for worshiping astral deities) they burned sacrifices to all the heavenly host and poured out libations to other gods." (Jer 19:13)
In summary the first Scriptural use of the phrase host of heaven is a warning to Israel not to exchange worship of the Creator for the worship of the creation that included the host of heaven.
The International Standard Bible Encyclopedia adds that…
Star-worship seems to have been an enticement to Israel from the first (Deuteronomy 4:19; 17:3; Amos 5:26; compare Acts 7:42,43), but attained special prominence in the days of the later kings of Judah. The name of Manasseh is particularly connected with it. This king built altars for "all the host of heaven" in the courts of the temple (2 Kings 21:3-5 = 3 For he rebuilt the high places which Hezekiah his father had destroyed; and he erected altars for Baal and made an Asherah, as Ahab king of Israel had done, and worshiped all the host of heaven and served them.4 And he built altars in the house of the LORD, of which the LORD had said, "In Jerusalem I will put My name 5 For he built altars for all the host of heaven in the two courts of the house of the LORD.").
Josiah destroyed these altars, and cleansed the temple from the idolatry by putting down the priests and burning the vessels associated with it (2 Kings 23:4-5 = Then the king commanded Hilkiah the high priest and the priests of the second order and the doorkeepers, to bring out of the temple of the LORD all the vessels that were made for Baal, for Asherah, and for all the host of heaven; and he burned them outside Jerusalem in the fields of the Kidron, and carried their ashes to Bethel. And he did away with the idolatrous priests whom the kings of Judah had appointed to burn incense in the high places in the cities of Judah and in the surrounding area of Jerusalem, also those who burned incense to Baal, to the sun and to the moon and to the constellations and to all the host of heaven.). (ISBE)
Unger's Dictionary explains that host of heaven referred to "The sun, moon, and stars, under the symbol of an army, in which the sun is considered king, the moon his vice-regent, and the stars and planets their attendants (cf. note Judges 5:20). The worship of the host of heaven was one of the earliest forms of idolatry and was common among the Israelites in the times of their turning away from the pure service of God (Unger, M. F., Harrison, R. K., Vos, H. F., Barber, C. J., and Unger, M. F. The New Unger's Bible dictionary. Chicago: Moody Press)
Baker Encyclopedia of the Bible - In the astrological cults of antiquity it was believed that celestial bodies were animated by spirits and thus constituted a living army that controlled heavenly destiny… Although warned against such pagan beliefs (Dt 4:19; 17:3), the Israelites fell into the practice of worshiping heavenly bodies, particularly during the Assyrian and Babylonian periods (2 Ki 17:16 = And they forsook all the commandments of the LORD their God and made for themselves molten images, even two calves, and made an Asherah and worshiped all the host of heaven and served Baal. 2 Kings 21:3, 5; 2 Chr 33:3, 5; Jer 8:2; Zeph 1:5). The corrective of this pagan practice was Israel’s belief in the Lord as the Creator of heaven and earth, the one who marshaled the heavenly bodies at his command and ordained them to perform a special function (Gen 1:14–19; 2:1; Neh 9:6; Ps 33:6; 103:21; 148:2; Is 40:26; 45:12)… Though the hosts are sometimes understood as the stars or angels, the tribes of Israel are also called “the hosts of the Lord” (Ex 12:41). The “host of heaven” referred to in Daniel 8:10, 11, appears to be figurative language referring to Israel, “the holy people” (cf. v 24 kjv) and God, the King of Israel is called “the Prince of the host.” (Elwell, W. A., & Beitzel, B. J. Baker Encyclopedia of the Bible. Grand Rapids, Mich.: Baker Book House)
As noted above, Host of Heaven can refer to literal "stars"…
Jer 33:22 As the host of heaven, cannot be counted and the sand of the sea cannot be measured (This comparison with the innumerable host of stars and immeasurable grains of sand is a reiteration of the promises to Abraham, cf Ge 15:5; 22:17 and serve as a reiteration of God's faithfulness to His covenant with Abraham = cf Josh 23:14 "not one word of all the good words which the LORD your God spoke concerning you has failed; all have been fulfilled for you, not one of them has failed."), so I will multiply the descendants of David My servant and the Levites who minister to Me.
Isa 34:4 And all the host of heaven will wear away and the sky will be rolled up like a scroll. All their hosts will also wither away as a leaf withers from the vine, or as one withers from the fig tree. (cf Isa 40:26, 45:12)
As the New Bible Dictionary emphasizes the distinction between heavenly bodies and heavenly beings can be problematic, noting that "The two meanings ‘celestial bodies’ [stars] and ‘angelic beings’ are inextricably intertwined." (New Bible Dictionary) (Bolding added)
In fact it is fair to say that the two basic meanings sometimes seem to overlap to such an extent that it is almost impossible to identify which meaning the writer meant to indicate in a given use. For example, look at the verses below
2Ki 21:3 For he [the evil king Manasseh] rebuilt the high places which Hezekiah his father had destroyed and he erected altars for Baal and made an Asherah, as Ahab king of Israel had done and worshiped all the host of heaven and served them.
Isa 24:21 So it will happen in that day, That the LORD will punish the host of heaven on high, and the kings of the earth on earth
Keeping these somewhat indistinct lines of separation in mind, remember not to lose sight of the more important point that Jehovah is the Commander of the Hosts regardless of whether they are literal stars or spirit beings.
Angelic beings, both "good and bad", are sometimes referred to as the "host of heaven". In the confrontation between wicked king Ahab and the prophet Micaiah in 1Ki 22:15-28 we see the host of heaven standing before God. Obviously host of heaven in this context does not refer to literal stars, but to evil spirits beings (in this case evil spirits as indicated by their own words) that compose the "celestial hosts of heaven".
1Kings 22:19 (parallel passage = 2Chr 18:18-28) "Micaiah said, "Therefore, hear the word of the LORD. I saw the LORD sitting on His throne, and all the host of heaven standing by Him on His right and on His left. 20 "The LORD said, 'Who will entice Ahab to go up and fall at Ramoth-gilead?' And one said this while another said that. 21 Then a spirit came forward and stood before the LORD and said, 'I will entice him.' 22 "The LORD said to him, 'How ?' And he said, 'I will go out and be a deceiving spirit in the mouth of all his prophets (The sovereign LORD of hosts permitted a deceiving spirit to control the prophets and give Ahab the wrong advice. Nonetheless, Ahab made a responsible choice, having been warned of the truth by Micaiah).' Then He said, 'You are to entice him and also prevail. Go and do so.'
Luke uses the parallel term heavenly host to refer to heavenly beings writing…
And suddenly there appeared with the angel a multitude of the heavenly host praising God, and saying "Glory to God in the highest, And on earth peace among men with whom He is pleased." (Luke 2:13-14)
Perhaps the main point to remember from this summary of the phrase host of heaven is that Jehovah Sabaoth is LORD of hosts, Commander in Chief, over both stars (celestial bodies) or angels (celestial beings), including both "good" and "fallen" angels. This truth is important to recall to mind when we find ourselves in spiritual warfare (we are always engaged in warfare whether we are aware of it or not) where the odds seem overwhelmingly against us. We can cry out to the One Who is LORD over ALL the "hosts", be they heavenly bodies or beings and He will hear our call for aid (see related study The LORD My Help (Jehovah Ezer)). This is a truth that Nebuchadnezzar testified to when he returned to his senses (Daniel 4):
Daniel 4:35-note "All the inhabitants of the earth are accounted as nothing, but He does according to His will in the host of heaven and among the inhabitants of earth and no one can ward off His hand Or say to Him, 'What have You done ?'
We need not wonder whether good or evil will prevail in the end. We need not worry that God’s creatures may frustrate His best intentions. To Jehovah Sabaoth, the eternal, infinitely perfect, self-existent, self-sufficient, holy, sovereign, loving, and gracious God, be glory forevermore. Amen
Related Resources -
The phrase "host (tsaba) of heaven" is found 17x (NAS) - Dt 4:19; 1Ki 22:19; 2Ki 17:16; 21:3, 5; 23:4-5; 2Chr 18:18; 33:3, 5; Isa 24:21; 34:4; Jer 8:2; 33:22; Da 4:35; 8:10; Zeph 1:5. Nelson's Bible Dictionary says this phrase refers to the "heavenly beings created by God and associated with Him in His rule over the world." However if you study the 17 uses above, some appear to be heavenly bodies rather than heavenly beings! For example, a simple reading of Dt 4:19 would favor celestial bodies over beings and Jer 33:22 clearly uses host of heaven to describe created bodies (stars). In Isa 34:4 host of heaven would seem to be more closely related to created bodies than created beings. On the other hand 1Ki 22:19 (and 2Chr 18:18) clearly refers to celestial beings (angels) and appears to include both good and bad (as deduced from what Jehovah asks in 1Ki 22:20!). Isa 24:21 says "the LORD will punish the host of heaven, on high, and the kings of the earth, on earth," which most clearly speaks of created beings (angels - in context demons). In several passages the meaning is somewhat ambiguous as in 2Ki 17:16, 2Ki 21:3, 2Ki 23:4, 5, 2Chr 33:3, 5, Jer 8:2, Zeph 1:5 each of which could refer either to the demonic beings or celestial bodies. In fact if one worships the latter (created bodies - cp the modern practice of Astrology) he or she would in effect be worshipping the former (demons behind the idol as Paul taught in 1Cor 10:20), so in that sense the two meanings are closely related.
The "host of heaven" has two basic meanings and the meaning is determined by the context of the passages used in Scripture. Both heavenly (celestial) bodies -- the sun, moon, stars and angels are referred to as the "host of heaven." These two meanings also often overlap when angels are sometimes also referred to as stars (Jdg 5:20; Job 25:5; 38:7, Rev 1:20). (Rapture Ready)
(4) Host of Heaven
The basic meaning of the root sb’ (tsaba). Although the most frequent meaning of the root may have to do with warfare or an army, it does not seem that this meaning is the most fundamental. At least some passages do not bear that meaning easily (Nu 4:3). It becomes a question then whether these passages should be explained as metaphorical extensions of the basic meaning “army” or taken as themselves illustrative of a broader basic meaning such as “group,” of which the examples meaning “army” are a specialization. In this light, is the host of heaven to be thought of as an army of heaven, or a group of beings inhabiting heaven? Contrary to some of the more standard lexical tools (BDB, KB), it would appear that comparative Sem. data does not support the meaning “army” as the basic force of the word. The Chicago Assyrian Dictionary gives the meaning of ābu as “group of people, contingent of workers, troop of soldiers.”
Dt 4:19 "And beware, lest you lift up your eyes to heaven and see the sun and the moon and the stars, all the host of heaven, and be drawn away and worship them and serve them, those which the LORD your God has allotted to all the peoples under the whole heaven.
1Ki 22:19 And Micaiah said, "Therefore, hear the word of the LORD. I saw the LORD sitting on His throne, and all the host of heaven standing by Him on His right and on His left.
2Ki 17:16 And they forsook all the commandments of the LORD their God and made for themselves molten images, even two calves, and made an Asherah and worshiped all the host of heaven and served Baal.
2Ki 21:3 For he rebuilt the high places which Hezekiah his father had destroyed; and he erected altars for Baal and made an Asherah, as Ahab king of Israel had done, and worshiped all the host of heaven and served them.
2Ki 21:5 For he built altars for all the host of heaven in the two courts of the house of the LORD.
2Ki 23:4 Then the king commanded Hilkiah the high priest and the priests of the second order and the doorkeepers, to bring out of the temple of the LORD all the vessels that were made for Baal, for Asherah, and for all the host of heaven; and he burned them outside Jerusalem in the fields of the Kidron, and carried their ashes to Bethel.
2Ki 23:5 And he did away with the idolatrous priests whom the kings of Judah had appointed to burn incense in the high places in the cities of Judah and in the surrounding area of Jerusalem, also those who burned incense to Baal, to the sun and to the moon and to the constellations and to all the host of heaven.
2Chr 18:18 And Micaiah said, "Therefore, hear the word of the LORD. I saw the LORD sitting on His throne, and all the host of heaven standing on His right and on His left.
2Chr 33:3 For he rebuilt the high places which Hezekiah his father had broken down; he also erected altars for the Baals and made Asherim, and worshiped all the host of heaven and served them.
2Chr 33:5 For he built altars for all the host of heaven in the two courts of the house of the LORD.
Isa 24:21 So it will happen in that day, That the LORD will punish the host of heaven, on high, And the kings of the earth, on earth.
Isa 34:4 And all the host of heaven will wear away, And the sky will be rolled up like a scroll; All their hosts will also wither away As a leaf withers from the vine, Or as one withers from the fig tree.
Jer 8:2 "And they will spread them out to the sun, the moon, and to all the host of heaven, which they have loved, and which they have served, and which they have gone after, and which they have sought, and which they have worshiped. They will not be gathered or buried; they will be as dung on the face of the ground.
Jer 33:22 'As the host of heaven cannot be counted, and the sand of the sea cannot be measured, so I will multiply the descendants of David My servant and the Levites who minister to Me.'"
Da 4:35 "And all the inhabitants of the earth are accounted as nothing, But He does according to His will in the host of heaven And among the inhabitants of earth; And no one can ward off His hand Or say to Him, 'What hast Thou done?'
Da 8:10 And it grew up to the host of heaven and caused some of the host and some of the stars to fall to the earth, and it trampled them down.
Zeph 1:5 "And those who bow down on the housetops to the host of heaven, And those who bow down and swear to the LORD and yet swear by Milcom,
Acts 7:42 "But God turned away and delivered them up to serve the host of heaven; as it is written in the book of the prophets, 'IT WAS NOT TO ME THAT YOU OFFERED VICTIMS AND SACRIFICES FORTY YEARS IN THE WILDERNESS, WAS IT, O HOUSE OF ISRAEL?