So the Jews grumbled about him, because he said, "I am the bread that came down from heaven." They said, "Is not this Jesus, the son of Joseph, whose father and mother we know? How does he now say, 'I have come down from heaven'?"
- John 6:41-42
Logic and reason are not sufficient tools with which to ultimately know Jesus. For logic and reason only have part of the picture in view. The rationality of the Jews sounded good, for they did know Jesus' mother and step-father. Yet they did not know the whole story, they did not see the whole picture as they imagined. True faith extends beyond mere reason and logic.
Remember what Jesus said to Peter after Peter proclaimed Jesus' true identity; (Mat 16:17) "Blessed are you, Simon Bar-Jonah! For flesh and blood has not revealed this to you, but my Father who is in heaven."
Just as it was the Heavenly Father that revealed to Peter who Jesus really is, so also it is with all of those who believe. So we see that logic and reason are not sufficient foundations for faith in Christ Jesus, for true faith in Him comes as a revelation from Him. Genuine faith is birthed through the Word and by the Spirit. It is a gift (Rom. 6:23).
All that said, throwing logic and reason away entirely would be like throwing out the baby out with the bath water. For even Paul reasoned with men in the synagogues, in the market places, and in the Areopagus (Acts 17:17-19).
Yet faith does not finally rest upon logic or reason but upon something much deeper, upon something accomplished by God, something revealed by Him.
And even if our gospel is veiled, it is veiled only to those who are perishing. In their case the god of this world has blinded the minds of the unbelievers, to keep them from seeing the light of the gospel of the glory of Christ, who is the image of God.
- 2 Cor. 4:3-4
For God, who said, "Let light shine out of darkness," has shone in our hearts to give the light of the knowledge of the glory of God in the face of Jesus Christ.
- 2 Cor. 4:6