Greek - to pneuma kai to hudor kai to haima kai oi treis eis to en eisin (3SPAI):
NLT the Spirit, the water, and the blood-- and all three agree.
ESV the Spirit and the water and the blood; and these three agree.
NIV the Spirit, the water and the blood; and the three are in agreement.
- there: 1Jn 5:7
- the spirit: 1Jn 5:6 Mt 26:26-28 28:19 Joh 15:26 Ro 8:16 Heb 6:4
- the water: Ac 2:2-4 2Co 1:22
- the blood: Heb 13:12 1Pe 3:21
- and these: Mk 14:56 Ac 15:15
- 1 John 5 Resources - Multiple Sermons and Commentaries
THE THREE WITNESSES OF JESUS CHRIST
Note: If you use the older version of the NAS (1977), you will find that the new version (1995) shifts the first clause of verse 8 (For there are three that bear witness) to verse 7. Here is the 1977 Version of 1Jn 5:8 "For there are three that bear witness (this clause in bold green is shifted to verse 7 in the 1995 NAS), the Spirit and the water and the blood; and the three are in agreement."
The Spirit - His testimony regarding Jesus Christ is discussed in the comments on 1Jn 5:6 (See discussion of how the Spirit testifies).
Whereas water and blood were mentioned before the Spirit in 1Jn 5:6, John now mentions the Spirit first. Henry Alford explains that “The Spirit is, of the three, the only living and active witness, properly speaking: besides, the water and the blood are no witnesses without Him, whereas He is independent of them, testifying both in them and out of them.”
Glenn Barker adds another reason the Spirit is mentioned first noting that "the Spirit provides what humanity is unable to acquire for itself. This witness of the Spirit accompanies every presentation of the word whether that presentation comes as a personal message or as the apostolic or inscripurated word." (Expositor's Bible Commentary)
The water and the blood - Although not every writer agrees, it seems most reasonable to see these have the same meaning as in John's previous mention in 1Jn 5:6 where he stated that Jesus came "by water and blood." As discussed earlier the water refers to Jesus' baptism marking the inception of His earthly ministry and the blood refers to the crucifixion marking the fulfillment of the redemptive purpose of His earthly ministry. For more discussion of the other interpretative views of water and blood see Steven Cole's note on 1Jn 5:6.
John MacArthur agrees that "It is best to see the water here as a reference to Christ's baptism and the blood as a reference to His death. Those two notable events bracketed the Lord's earthly ministry, and in both of them the Father testified concerning His Son."
Kistemaker agrees observing that "If we understand water and blood to represent the baptism and death of Christ, we think of the earthly ministry of Jesus Christ. Jesus identified Himself with His people when He was baptized, and He redeemed them when He died on the cross. Water and blood, therefore, are redemptive symbols for the believer. The believer accepts the truth that Jesus Christ came by water and blood. He knows that the Spirit testifies to this truth. Moreover, he believes that the Son of God came to cleanse his people from sin and to redeem them through his death. For the believer, then, these truths are basic."
THREE WITNESSES: ONE MESSAGE
The three are in agreement - Literally the Greek reads "the three are into the one." The verb (are) is in the present tense signifying the three witnesses are continually of one accord, in perfect agreement that Jesus is the Messiah, the Son of God.
As discussed earlier, the validity of personal testimony in the OT was linked to a specific number of credible witnesses, specifically “two or three witnesses” were necessary to establish guilt or innocence on criminal charges (Dt 19:15) and only on this basis could a person be sentenced to death (Dt 17:6). Jesus applied the principle of “two or three witnesses” to his instructions for resolving disputes in his church (Mt 18:15-16). Paul used the standard to determine whether an accusation could be sustained against an elder (1Ti 5:19). In his second letter to the Corinthians, Paul sees his thrice repeated testimony alone, whether in person or by letter, as satisfying the requirement of two or three witnesses" (2Cor 13:1-3). The writer of the book of Hebrews alludes to this pattern writing that "Anyone who has set aside the Law of Moses dies without mercy on [the testimony of] two or three witnesses. How much severer punishment do you think he will deserve who has trampled under foot the Son of God, and has regarded as unclean the blood of the covenant by which he was sanctified, and has insulted the Spirit of grace?" (Heb 10:28-29-note) In this passage the writer points out the "greater testimony" of two witnesses, the Son of God and the Spirit of grace.
Vincent says that the three are in agreement signifies that “they converge upon the one truth, Jesus Christ, the Son of God, come in the flesh.” Henry Alford adds that the three witnesses "Concur in the one, contribute to one and the same result, namely, the truth that Jesus is the Christ, and that we have life in Him."
Kistemaker - John writes that “the three are in agreement.” He means that all three witnesses say the same thing; before a court of law the factual evidence of Jesus’ baptism (water) and death (blood) is in complete agreement with the testimony of the Holy Spirit. A person cannot accept either one or two of the witnesses and omit the third. All three stand together. Many scholars suggest that the terms water and blood in verse 8 refer to the sacraments of baptism and the Lord’s Supper. However, the difficulty with this view is that the Spirit, whom John mentions first in rank, cannot become a third sacrament. Because John gives no indication that the phrase water and blood has a meaning different from that in verse 6, we do well to accept the same interpretation for 1Jn 5:6 and 1Jn 5:8. (Baker's NT Commentary)
Smalley comments that John is “implying that the Spirit, water and blood converge on the same point, and work together toward the same result: that of establishing the truth that Jesus is Messiah and Son of God.”
As Hiebert says "The agreement of these three witnesses is in striking contrast to the response of the false witnesses at the trial of Jesus who could not agree in establishing a valid charge against Christ (Mt. 26:59-61; Mk 14:55-59). But these three witnesses unite in bearing a consistent witness “to the reality of God’s work in Christ by the Spirit, both in the believer and in the world; they declare jointly that through Jesus good is ultimately shown to be stronger than evil (cf. 1Jn 5:5). (The Epistles of John- An Expositional Commentary).
John Stott - The false witnesses at the trial of Jesus, seeking to discredit him, did not agree (Mark 14:56, 59); the true witnesses, however, the Spirit, the water and the blood, seeking to accredit him, are in perfect agreement.
Steven Cole - John’s point is that God’s threefold witness to His Son—the Spirit, the water, and the blood—is trustworthy. In a court of law, truth is established when numerous witnesses say the same thing and when those witnesses are shown to have credible character. John shows us that the three witnesses all agree, and they are not just the testimony of men, but of God Himself. (1 John 5:5-13 Is Christianity Merely Psychological?)