J.C. Ryle on Prayer

But this I do say, that not praying is a clear proof that a man is not yet a true Christian. He cannot really feel his sins. He cannot love God. He cannot feel himself a debtor to Christ. He cannot long after holiness. He cannot desire heaven. He has yet to be born again. He has yet to be made a new creature. He may boast confidently of election, grace, faith, hope, and knowledge, and deceive ignorant people. But you may rest assured it is all vain talk if he does not pray.

—J.C. Ryle
A Call to Prayer