The more wood you pile on a fire the more heat you get, and thus it is with God - the more you think on Him the more you are fired with love and fervor towards Him. He who loves the Lord is always mindful of Him, and remembrance of God begets prayer.
Not he is chaste in whom shameful thoughts stop in time of struggle, work and endeavor, but he who by the trueness of his heart makes chaste the vision of his mind not letting it stretch out towards unseemly thoughts.
As water standing behind an earth dam, and finding an aperture, washes it wider and wider and filters through it, if we do not strengthen the dam, or strengthen it insufficiently, at last, with growing weakness on our part and with repeated efforts, the water gets through with greater and greater force, so that at last it becomes very difficult, and even impossible to stop it; so also with malice hidden in the heart of man: if we let it pierce through once, twice, and thrice, it will pour out more and more powerfully, & may at last break through and overflow your dam.