The word “faith” is translated from the Greek piʹstis, primarily conveying the thought of confidence, trust, firm persuasion. Depending on the context, the Greek word may also be understood to mean “faithfulness” or “fidelity.”​—1Th 3:7; Tit 2:10.

The Scriptures tell us: “Faith is the assured expectation of things hoped for, the evident demonstration of realities though not beheld.” (Heb  11:1) “Assured expectation” translates the Greek word hy·poʹsta·sis. This term is common in ancient papyrus business documents. It conveys the idea of something that underlies visible conditions and guarantees a future possession. In view of this, Moulton and Milligan suggest the rendering: “Faith is the title deed of things hoped for.” (Vocabulary of the Greek Testament, 1963, p. 660) The Greek word eʹleg·khos, rendered “evident demonstration,” conveys the idea of bringing forth evidence that demonstrates something, particularly something contrary to what appears to be the case. Thereby this evidence makes clear what has not been discerned before and so refutes what has only appeared to be the case. “The evident demonstration,” or evidence for conviction, is so positive or powerful that faith is said to be it.

Faith is, therefore, the basis for hope and the evidence for conviction concerning unseen realities. The entire body of truths delivered by Jesus Christ and his inspired disciples constitutes the true Christian “faith.” (Joh 18:37; Ga 1:7-9; Ac 6:7; 1Ti 5:8) Christian faith is based on the complete Word of God, including the Hebrew Scriptures, to which Jesus and the writers of the Christian Greek Scriptures frequently referred in support of their statements.

Faith is based on concrete evidence. The visible creative works testify to the existence of an invisible Creator. (Ro 1:20) The actual occurrences taking place during the ministry and earthly life of Jesus Christ identify him as the Son of God. (Mt 27:54; see JESUS CHRIST.) God’s record of providing for his earthly creatures serves as a valid basis for believing that he will surely provide for his servants, and his record as a Giver and Restorer of life lends ample evidence to the credibility of the resurrection hope. (Mt 6:26, 30, 33; Ac 17:31; 1Co 15:3-8, 20, 21) Furthermore, the reliability of God’s Word and the accurate fulfillment of its prophecies instill confidence in the realization of all of His promises. (Jos 23:14) Thus, in these many ways, “faith follows the thing heard.”​—Ro 10:17; compare Joh 4:7-30, 39-42; Ac 14:8-10.

So faith is not credulity. The person who may ridicule faith usually has faith himself in tried and trusted friends. The scientist has faith in the principles of his branch of science. He bases new experiments on past discoveries and looks for new discoveries on the basis of those things already established as true. Likewise, the farmer prepares his soil and sows the seed, expecting, as in previous years, that the seed will sprout and that the plants will grow as they receive the needed moisture and sunshine. Therefore faith in the stability of the natural laws governing the universe actually constitutes a foundation for man’s plans and activities. Such stability is alluded to by the wise writer of Ecclesiastes: “The sun also has flashed forth, and the sun has set, and it is coming panting to its place where it is going to flash forth. The wind is going to the south, and it is circling around to the north. Round and round it is continually circling, and right back to its circlings the wind is returning. All the winter torrents are going forth to the sea, yet the sea itself is not full. To the place where the winter torrents are going forth, there they are returning so as to go forth.”​—Ec 1:5-7.

In the Hebrew Scriptures, the word ʼa·manʹ and other words closely related convey the sense of trustworthiness, faithfulness, steadiness, steadfastness, being firmly established, long-lasting. (Ex 17:12; De 28:59; 1Sa 2:35; 2Sa 7:16; Ps 37:3) One related noun (ʼemethʹ) usually denotes “truth,” but also “faithfulness” or “trustworthiness.” (2Ch 15:3, ftn; 2Sa 15:20; compare Ne 7:2, ftn.) The familiar term “Amen” (Heb., ʼa·menʹ) also comes from ʼa·manʹ.​—See AMEN.

Ancient Examples of Faith. Each one of the “so great a cloud of witnesses” mentioned by Paul (Heb 12:1) had a valid basis for faith. For example, Abel certainly knew about God’s promise concerning a “seed” that would bruise “the serpent” in the head. And he saw tangible evidences of the fulfillment of the sentence Jehovah pronounced upon his parents in Eden. Outside Eden, Adam and his family ate bread in the sweat of their face because the ground was cursed and, therefore, produced thorns and thistles. Likely Abel observed that Eve’s craving was for her husband and that Adam dominated his wife. Undoubtedly his mother commented about the pain attending her pregnancy. Then, too, the entrance to the garden of Eden was being guarded by cherubs and the flaming blade of a sword. (Ge 3:14-19, 24) All of this constituted an “evident demonstration,” giving Abel the assurance that deliverance would come through the ‘seed of promise.’ Therefore, prompted by faith, he “offered God a sacrifice,” one that proved to be of greater worth than that of Cain.​—Heb 11:1, 4.

Abraham had a firm basis for faith in a resurrection, for he and Sarah had experienced the miraculous restoration of their reproductive powers, which was, in a sense, comparable to a resurrection,  allowing Abraham’s family line to continue through Sarah. Isaac was born as the result of this miracle. When told to offer up Isaac, Abraham had faith that God would resurrect his son. He based such faith on God’s promise: “It is by means of Isaac that what will be called your seed will be.”​—Ge 21:12; Heb 11:11, 12, 17-19.

Evidence for genuine conviction was also involved in the case of those who came to or who were brought to Jesus to be healed. Even if not eyewitnesses personally, they at least had heard about Jesus’ powerful works. Then, on the basis of what they saw or heard, they concluded that Jesus could heal them also. Moreover, they were acquainted with God’s Word and thus were familiar with the miracles performed by the prophets in times past. Upon hearing Jesus, some concluded that he was “The Prophet,” and others that he was “the Christ.” In view of this, it was most fitting for Jesus on occasion to say to those who were healed, “Your faith has made you well.” Had those persons not exercised faith in Jesus, they would not have approached him in the first place and, therefore, would not have received healing for themselves.​—Joh 7:40, 41; Mt 9:22; Lu 17:19.

Likewise, the great faith of the army officer who entreated Jesus in behalf of his manservant rested on evidence, on the basis of which he concluded that Jesus’ merely ‘saying the word’ would result in the healing of his manservant. (Mt 8:5-10, 13) However, we note that Jesus healed all who came to him, not requiring faith greater or less according to their disease, nor failing to heal any of these with the excuse that he could not do it because their faith was not strong enough. Jesus performed these healings as a witness, to establish faith. In his home territory, where much unfaithfulness was expressed, he chose not to perform many powerful works, not because of inability, but because the people refused to listen and were unworthy.​—Mt 13:58.

Christian Faith. To be acceptable to God, it is now necessary for one to exercise faith in Jesus Christ, and this makes possible a righteous standing with God. (Ga 2:16) Those lacking such faith are rejected by Jehovah.​—Joh 3:36; compare Heb 11:6.

Faith is not the possession of all persons, as it is a fruit of God’s spirit. (2Th 3:2; Ga 5:22) And a Christian’s faith is not static, but it grows. (2Th 1:3) Hence, the request of Jesus’ disciples, “Give us more faith,” was very appropriate, and he did provide them the foundation for increased faith. He supplied them with greater evidence and understanding on which to base their faith.​—Lu 17:5.

The entire life course of a Christian is actually governed by faith, enabling him to overcome mountainlike obstacles that would hinder his service to God. (2Co 5:7; Mt 21:21, 22) Additionally, there must be works consistent with and in display of faith, but works of the Mosaic Law are not required. (Jas 2:21-26; Ro 3:20) Trials can strengthen faith. Faith serves as a protective shield in the Christian’s spiritual warfare, helping him to overcome the Devil and be a conqueror of the world.​—1Pe 1:6, 7; Eph 6:16; 1Pe 5:9; 1Jo 5:4.

But faith cannot be taken for granted, because lack of faith is ‘the sin that so easily entangles one.’ To maintain a firm faith requires putting up a hard fight for it, resisting men who could plunge one into immorality, combating the works of the flesh, avoiding the snare of materialism, shunning faith-destroying philosophies and traditions of men, and, above all, looking “intently at the Chief Agent and Perfecter of our faith, Jesus.”​—Heb 12:1, 2; Jude 3, 4; Ga 5:19-21; 1Ti 6:9, 10; Col 2:8.