Adam S. Miller said this quote

They say in Zen, waking up to life requires three things: great faith, great doubt, and great effort. Faith isn’t a way of going to sleep. It’s the work of waking up. And, in order to wake up, you’ll need both great faith and great doubt. In itself, doubt is neither good nor bad. Its value depends on what you do with it. You can doubt what’s real in order to stay asleep or you can doubt your daydreams in order to wake up. You can use doubt to protect you from the truth or you can use doubt to leave you vulnerable to it. You’ll have doubts regardless. Repurpose them for the sake of faith. Saving doubt is a strong solvent that can burn holes in your [worldview] and lead you back to the work of being faithful to life and, thus, to God. Practicing doubt for the sake of faith is hard work and it demands great effort. Great faith, great doubt, great effort.