A failure to understand something does not mean it is irrational. It may simply mean that it lies on the far side of our limited abilities to take things in and make complete sense of them.
Within each of us exists the image of God, however disfigured and corrupted by sin it may presently be. God is able to recover this image through grace as we are conformed to Christ. Just as the figure of David lay hidden within the marble, discernible only to the eye of its creator, so the image of God (however tarnished by sin) lies within us, see and known by God Himself. Yet God loves us while we are still sinners. He doesn't have to wait until we stop sinning. Acceptance of His love is a major step along the road that leads to our liberation from the tyranny of sin.
All the important things in life lie beyond reason... and that's just the way things are.
Beneath all the rhetoric about relevance lies a profoundly disturbing possibility - that people may base their lives upon an illusion, upon a blatant lie. The attractiveness of a belief is all too often inversely proportional to its truth... To allow "relevance" to be given greater weight than truth is a mark of intellectual shallowness and moral irresponsibility.