"Praying and sinning will never live together in the same heart. Prayer will consume sin, or sin will choke prayer. . . . Diligence in prayer is the secret of eminent holiness. Without controversy there is a vast difference among true Christians. . . . I believe the difference in nineteen cases out of twenty arises from different habits about private prayer. I believe that those who are not eminently holy pray little, and those who are eminently holy pray much."
-J.C. Ryle (Practical Religion)