“The supreme function of reason is to show man that some things are beyond reason,” is how Blaise Pascal put it. Something would not require faith if the proof of it was absolute. According to Philip Yancey, the author of “The Jesus I Never Knew,” “Faith requires the possibility of rejection, or it is not faith.”

Perhaps the key to understanding why faith is prized within the Christian tradition is that it involves trust that would not be needed if the existence of God were subject to a mathematical proof. What God is seeking is not our intellectual assent so much as a relationship with us. That is, after all, one of the purposes of the incarnation of God in Jesus.

Every meaningful relationship — parent-child, spouse to spouse, friend to friend — involves some degree of trust. It is better and more vivifying to be the object of someone’s trust rather than the last person standing after a series of logical deductions. That’s true for us as individuals, and it can be true for God as well.

Faith demonstrates human trust in him — and, according to James Forsyth, pastor at McLean Presbyterian Church in Virginia, which my family attends, it demonstrates that we accept God’s love for us. “There is a force within love that longs to be received,” he says.

Craig Barnes, the president of Princeton Theological Seminary, told me, “Faith is a greater blessing than proof because it gives us a relationship with Jesus. All good relationships are bound together by love. And love is always an expression of faith.” He also pointed out that proofs don’t necessarily inspire belief. Toward the end of his Gospel, Matthew mentions that some still doubted after they looked right at the risen Christ. (“When they saw him, they worshiped him; but some doubted.”)

Some of those who witnessed the miracles of Jesus eventually sought to kill him. And Judas, one of Jesus’ original disciples, betrayed him with a kiss. So sensory experience isn’t enough to compel belief and allegiance.

Our most important forms of knowledge rarely come from logic or proof, according to Cherie Harder, the president of the Trinity Forum. Citing the work of the theologian Lesslie Newbigin, she says it comes through a more personal knowledge. For example, I know my wife loves me because I know her, I know her heart, I know her character, and because I trust her. “Your knowledge of her is less about physical certainty,” Ms. Harder wrote to me, “and more about a well-placed confidence in who she is (a faith in her that is qualitatively different, and far more personal and holistic, than intellectual certainty).”