The primary word in the New Testament for faith is the Greek noun πίστις (Pistis, G4102). According to Joseph Henry Thayer, Pistis primarily means the "conviction of the truth of anything, belief; in the NT of a conviction or belief respecting man's relationship to God and divine things, generally with the included idea of trust and holy fervour born of faith and joined with it". According to my Bible software (TheWord), it is used 227x in the NA28. William D. Mounce says that 'Pistis means "belief, trust, confidence," though it can also mean "faithfulness."' If we may at the outset observe, the basic meaning of the word has to do with conviction, trust, reliance, and confidence. It has nothing to do with "faith without evidence." Louis Berkhof observes:
In classical Greek. The word Pistis has two meanings in classical Greek. It denotes: (a) a conviction based on confidence in a person and in his testimony, which as such is distinguished from knowledge resting on personal investigation; and (b) the confidence itself on which such a conviction rests. This is more than a mere intellectual conviction that a person is reliable; it presupposes a personal relation to the object of confidence, a going out of one's self, to rest in another. The Greeks did not ordinarily use the word in this sense, to express their relation to the gods, since they regarded these as hostile to men, and therefore as objects of fear rather than of trust.
Now let us observe the different uses of the noun Pistis in the New Testament. First of all, there are a few instances in which it is used in a passive sense of faithfulness. This is the case in Romans 3:3 when Paul says, "Does [the Jews'] faithlessness [ἀπιστία, apistia] nullify the faithfulness [πίστιν, pistin] of God?" Or in Galatians 5:22 of the fruit of "faithfulness [πίστις, Pistis]", or in Matthew 23:2, "the weightier matters of the law: justice and mercy and faithfulness [πίστιν, pistin]." It may be used in this sense in Revelation 13:10 when John speaks of the "the endurance and faith [πίστις, Pistis] of the saints" amidst persecution. In Titus 2:10, slaves are called to show "all good faith [πίστιν, pistin]" toward their masters "so that in everything they may adorn the doctrine of God our Savior."
The other senses in which Pistis is used are active. The first is the act of believing. So, the New Testament speaks of faith in God in general. Jesus said to His disciples, "Have faith in God [πίστιν θεοῦ, pistin theou]" (Mark 11:22). Paul says to the Thessalonian church that their "faith in God [ἡ πίστις...τὸν θεὸν, he Pistis...ton theon] has gone forth everywhere" (1Thess. 1:8). An element of "the elementary doctrine of Christ" is "faith toward God [πίστεως ἐπὶ θεόν, pisteus epi theon]" (Heb. 6:1). Peter says that through Christ we are "believers in God" (the adjective of Pistis), so that our "f...