It is notable that only the book of Romans surpasses the book of Hebrews (click to study the uses of pistis in Hebrews) in the number of uses of pistis (Romans = 35, Hebrews = 31, out of 243 NT uses) Click for links to all 243 uses of pistis (NAS) which is translated: faith, 238; faithfulness, 3; pledge, 1; proof, 1.

As pistis relates to God, it is the conviction that God exists and is the Creator and Ruler of all things well as the Provider and Bestower of eternal salvation through Christ. As faith relates to Christ it represents a strong and welcome conviction or belief that Jesus is the Messiah, through Whom we obtain eternal salvation and entrance into the Kingdom of Heaven. Stated another way, eternal salvation comes only through belief in Jesus Christ and no other way.

See related studies on the specific phrases (1) "the faith" and (2) the "obedience of faith". See also study on pistos

True faith that saves one's soul includes at least three main elements

(1) firm persuasion or firm conviction,

(2) a surrender to that truth and

(3) a conduct emanating from that surrender. In sum, faith shows itself genuine by a changed life. (Click here for W E Vine's similar definition of faith)

Respected theologian Louis Berkhof defines genuine faith in essentially the same way noting that it includes an intellectual element (notitia), which is

a positive recognition of the truth”; an emotional element (assensus), which includes “a deep conviction of the truth”; and a volitional element (fiducia), which involves “a personal trust in Christ as Savior and Lord, including a surrender … to Christ.” (Louis Berkhof, Systematic Theology. Grand Rapids: Eerdmans, 1939)

Faith is relying on what God has done rather than on one’s own efforts. In the Old Testament, faith is rarely mentioned. The word trust is used frequently, and verbs like believe and rely are used to express the right attitude to God. The classic example is Abraham, whose faith was reckoned as righteousness (Ge 15:6). At the heart of the Christian message is the story of the cross: Christ’s dying to bring salvation. Faith is an attitude of trust in which a believer receives God’s good gift of salvation (Acts 16:30,31) and lives in that awareness thereafter (Gal 2:20; cf. Heb 11:1).

J. B. Lightfoot discusses the concept of faith in his commentary on Galatians. He notes that in Hebrew, Greek, and Latin, the definition of the word for faith

"hovers between two meanings: trustfulness, the frame of mind which relies on another; and trustworthiness, the frame of mind which can be relied upon...the senses will at times be so blended together that they can only be separated by some arbitrary distinction. The loss in grammatical precision is often more than compensated by the gain in theological depth...They who have faith in God are steadfast and immovable in the path of duty."

Faith, like grace, is not static. Saving faith is more than just understanding the facts and mentally acquiescing. It is inseparable from repentance, surrender, and a supernatural longing to obey. None of those responses can be classified exclusively as a human work, any more than believing itself is solely a human effort.

Faith is manifest by not believing in spite of evidence but obeying in spite of consequence. John uses the related verb pisteuo to demonstrate the relationship between genuine faith and obedience writing...

"He who believes (present tense = continuous) in the Son has eternal life; but he who does not obey the Son shall not see life, but the wrath of God abides on him." (John 3:36)

Charles Swindoll commenting on faith and obedience in John 3:36 concludes that...

In 3:36 the one who “believes in the Son has eternal life” as a present possession. But the one who “does not obey the Son shall not see life.” To disbelieve Christ is to disobey Him. And logically, to believe in Christ is to obey Him. As I have noted elsewhere, “This verse clearly indicates that belief is not a matter of passive opinion, but decisive and obedient action.” (quoting J. Carl Laney)...Tragically many people are convinced that it doesn’t really matter what you believe, so long as you are sincere. This reminds me of a Peanuts cartoon in which Charlie Brown is returning from a disastrous baseball game. The caption read, “174 to nothing! How could we lose when we were so sincere?” The reality is, Charlie Brown, that it takes more than sincerity to win the game of life. Many people are sincere about their beliefs, but they are sincerely wrong!" (Swindoll, C. R., & Zuck, R. B. Understanding Christian Theology.: Thomas Nelson Publishers) (This book is recommended if you are looking for a very readable, non-compromising work on "systematic theology". Wayne Grudem's work noted above is comparable.)

Subjectively faith is firm persuasion, conviction, belief in the truth, veracity, reality or faithfulness (though rare). Objectively faith is that which is believed (usually designated as "the faith"), doctrine, the received articles of faith. Click  separate study of "the faith (pistis)"

True faith is not based on empirical evidence but on divine assurance.

Spurgeon wrote that...

Faith is the foot of the soul by which it can march along the road of the commandments.

When missionary John Paton  was translating the Scripture for the South Sea islanders, he was unable to find a word in their vocabulary for the concept of believing, trusting, or having faith. He had no idea how he would convey that to them. One day while he was in his hut translating, a native came running up the stairs into Paton's study and flopped in a chair, exhausted. He said to Paton,

“It’s so good to rest my whole weight in this chair.”

John Paton had his word: Faith is resting your whole weight on God. That word went into the translation of their New Testament and helped bring that civilization of natives to Christ. Believing is putting your whole weight on God. If God said it, then it’s true, and we’re to believe it.

Nothing before, nothing behind,
The steps of faith
Fall on the seeming void, and find
The rock beneath -- Whittier

Clearly faith is a key word in Hebrews. Study the 31 uses of pistis in Hebrews in context (click the Scripture links to go to the notes on each verse)...

Hebrews 4:2 - For indeed we have had good news preached to us, just as they also; but the word they heard did not profit them, because it was not united by faith in those who heard.

Hebrews 6:1 - Therefore leaving the elementary teaching about the Christ, let us press on to maturity, not laying again a foundation of repentance from dead works and of faith toward God,

Hebrews 6:12 -so that you will not be sluggish, but imitators of those who through faith and patience inherit the promises.

Hebrews 10:22 - let us draw near with a sincere heart in full assurance of faith, having our hearts sprinkled clean from an evil conscience and our bodies washed with pure water.

Hebrews 10:38 - BUT MY RIGHTEOUS ONE SHALL LIVE BY FAITH; AND IF HE SHRINKS BACK, MY SOUL HAS NO PLEASURE IN

Hebrews 10:39 - But we are not of those who shrink back to destruction, but of those who have faith to the preserving of the soul.

Hebrews 11:1 - Now faith is the assurance of things hoped for, the conviction of things not seen.

Hebrews 11:3 - By faith we understand that the worlds were prepared by the word of God, so that what is seen was not made out of things which are visible.

Hebrews 11:4 - By faith Abel offered to God a better sacrifice than Cain, through which he obtained the testimony that he was righteous, God testifying about his gifts, and through faith, though he is dead, he still speaks.

Hebrews 11:5 - By faith Enoch was taken up so that he would not see death; AND HE WAS NOT FOUND BECAUSE GOD TOOK HIM UP; for he obtained the witness that before his being taken up he was pleasing to God.

Hebrews 11:6 - And without faith it is impossible to please Him, for he who comes to God must believe that He is and that He is a rewarder of those who seek Him.

Hebrews 11:7 - By faith Noah, being warned by God about things not yet seen, in reverence prepared an ark for the salvation of his household, by which he condemned the world, and became an heir of the righteousness which is according to faith.

Hebrews 11:8 - By faith Abraham, when he was called, obeyed by going out to a place which he was to receive for an inheritance; and he went out, not knowing where he was going.

Hebrews 11:9 - By faith he lived as an alien in the land of promise, as in a foreign land, dwelling in tents with Isaac and Jacob, fellow heirs of the same promise;

Hebrews 11:11 - By faith even Sarah herself received ability to conceive, even beyond the proper time of life, since she considered Him faithful who had promised.

Hebrews 11:13 - All these died in faith, without receiving the promises, but having seen them and having welcomed them from a distance, and having confessed that they were strangers and exiles on the earth.

Hebrews 11:17 - By faith Abraham, when he was tested, offered up Isaac, and he who had received the promises was offering up his only begotten son;

Hebrews 11:20 - By faith Isaac blessed Jacob and Esau, even regarding things to come.

Hebrews 11:21 - By faith Jacob, as he was dying, blessed each of the sons of Joseph, and worshiped, leaning on the top of his staff.

Hebrews 11:22 - By faith Joseph, when he was dying, made mention of the exodus of the sons of Israel, and gave orders concerning his bones.

Hebrews 11:23 - By faith Moses, when he was born, was hidden for three months by his parents, because they saw he was a beautiful child; and they were not afraid of the king's edict.

Hebrews 11:24 - By faith Moses, when he had grown up, refused to be called the son of Pharaoh's daughter,

Hebrews 11:27 - By faith he left Egypt, not fearing the wrath of the king; for he endured, as seeing Him who is unseen.

Hebrews 11:28 - By faith he kept the Passover and the sprinkling of the blood, so that he who destroyed the firstborn would not touch them.

Hebrews 11:29 -By faith they passed through the Red Sea as though they were passing through dry land; and the Egyptians, when they attempted it, were drowned.

Hebrews 11:30 - By faith the walls of Jericho fell down after they had been encircled for seven days.

Hebrews 11:31 - By faith Rahab the harlot did not perish along with those who were disobedient, after she had welcomed the spies in peace.

Hebrews 11:33 -who by faith conquered kingdoms, performed acts of righteousness, obtained promises, shut the mouths of lions,

Hebrews 11:39 - And all these, having gained approval through their faith, did not receive what was promised,

Hebrews 12:2 - fixing our eyes on Jesus, the author and perfecter of faith, who for the joy set before Him endured the cross, despising the shame, and has sat down at the right hand of the throne of God.

Hebrews 13:7 - Remember those who led you, who spoke the word of God to you; and considering the result of their conduct, imitate their faith.