O the starting-holes that the heart has in the time of prayer! None knows how many by-ways the heart has, and back-lanes, to slip away from the presence of God. How much pride also, if enabled with expressions! How much hypocrisy, if before others! And how little conscience is there made of prayer between God and the soul in secret, unless the Spirit of supplication be there to help! When the Spirit gets into the heart, then there is prayer indeed, and not till then.
John Bunyan, Prayer, p. 32