Faith is not a leap into the dark without reason, but a rational and trust-filled response to the objective truth of God as He has revealed Himself in Christ. Rather than believing in defiance of evidence, faith relies upon the testimony of God, which is anchored in history and affirmed by the inward witness of the Holy Spirit.
The biblical definition of faith provided in demonstrates that faith is not a mere feeling or a flight from reality. The author describes faith as the 'substance of things hoped for, the conviction of things not seen.' Reformed theology, as seen in , interprets this 'substance' (hypostasis) as a firm confidence or a prop upon which the mind rests. It is not belief without evidence, but a 'certain and secure possession' of the promises of God. Because the things pertaining to salvation are beyond the reach of our physical senses, we do not handle them as we handle worldly objects. Instead, we behold them in the Word of God. The conviction (elenchos) of things not seen is effectively the appearance of things not otherwise apparent. Therefore, faith is an intelligent reception of divine truth, where the mind is persuaded of the truthfulness of God's Word with a certainty that surpasses the clarity of physical demonstration.
Saving faith is not a blind, irrational act; it involves a clear progression of knowledge, belief, and trust. As articulated in , faith must have a foundation, and that foundation is the knowledge of the gospel. One cannot believe in a Savior they have not heard of. This knowledge includes the understanding of God's existence, His righteousness, and the necessity of the substitutionary work of Christ. Once the mind is informed by Scripture, the soul assents to these truths, believing them to be objective reality—just as one would believe a credible witness. Finally, faith culminates in trust (or 'resting'), which is the act of the whole person committing themselves to the object of their belief. The defines this beautifully: 'Faith in Jesus Christ is a saving grace, whereby we receive and rest upon him alone for salvation, as he is offered to us in the gospel.' This is not 'believing without evidence,' but rather 'believing upon the testimony of God' who cannot lie.
The charge that faith is 'irrational' usually rests on an evidentialist standard — the demand that a belief counts as rational only if it is propped up by sufficient evidence. As the philosopher Alvin Plantinga argued in Warranted Christian Belief, that standard proves too much: held consistently, it would force us to give up beliefs no reasonable person doubts — that other people have minds, that the world did not begin five minutes ago, that the past is real — none of which we infer from evidence. Plantinga's term for such convictions is properly basic, and belief in God, he contends, can be properly basic in just the same way. As discussed in , it need not pass through a narrow 'evidentialist toll-gate' to be rational. Plantinga presses the point further still: one cannot show that Christian belief is irrational without first assuming it is false, for if it is true, it is very likely warranted — the product of our God-given capacity to know Him. None of this pits faith against evidence. The gospel appeals to creation, which declares God's glory (), and to the historical reality of the resurrection. As noted in , it offers itself to examination — resting on events that had witnesses and a record that has endured rigorous criticism. We are not asked to abandon our intellect but to bring it to a rational Creator who made the world to be known. Faith, then, is the rational response of a creature made to know its Maker.
While some modern perspectives view faith as a heroic 'leap into the dark' or purely subjective feeling, the gospel presents something far more substantial. The Christian 'leap of faith' is not a leap away from evidence into thin air, but a leap toward a real Christ who stands on solid ground. In , it is argued that while faith must be deeply personal and self-involving—engaging the heart as well as the mind—it is faith in an object who is objectively there. The passion of the believer is warranted because the object of that passion (Jesus Christ) is the living Savior who actually rose from the dead. We are not asked to commit ourselves to 'nothing in particular,' but to the testimony that God has provided. When we trust Him, we are clinging to the Rock, just as the limpet clings to its foundation. This is a reasonable trust, based on the character of the One who is worthy of it, and who has made Himself known in the gospel so that we might have life.