“People who believe more must not be hard on those who believe less. Why? Because faith ultimately is not a virtue; it’s a gift.
“If you want to believe but can’t, stop looking inside; go to Jesus and say, ‘Help me believe.’ Go to him and say, ‘So you’re the one who gives faith! I’ve been trying to work it out by reasoning and thinking and meditating and going to church in hopes that a sermon will move me — I’ve been trying to get faith by myself. Now I see that you’re the source of faith. Please give it to me.’ If you do that, you’ll find that Jesus has been seeking you — he’s the author of faith, the provider of faith, and the object of faith.”
Tim Keller in King’s Cross: The Story of the World in the Life of Jesus