I believe, help my unbelief

A father brought his sick son to the disciples, but they couldn't help. Then he said to Jesus: if you can do anything, help us. Jesus turned those words around. It's not about what he can do, but about faith.

The father's answer is one of the most honest prayers in the Bible: Lord, I believe; help thou mine unbelief. Faith and doubt in one sentence. Jesus didn't turn him away. He healed the boy. You don't have to believe perfectly before you may ask.