And so it comes about that the desire of the flesh and of the spirit meeting in such a conflict and mutually contradictory, the will of the soul which is not prepared to surrender itself entirely to carnal desires nor yet to the toilsome labor of virtue, is moderated, so to say, by a just balance, while the struggle that goes on gives no place to that more dangerous free will of the soul, and puts a sort of equal weight into each of the scales which draws with accuracy a limit between flesh and spirit, and allows on the one hand the mind aflame with the spirit’s fire to have no greater weight, nor on the other the flesh stung with the goads of sin to prevail. And while this warfare is daily occurring in us for our good, we are compelled to approach that fourth thing of which we would have none, namely, that we should attain to purity of heart not by idleness of freedom from care, but by constant toil and contrition of spirit, and that we should retain chastity of the flesh by strict abstinence and fastings, temperance and watchfulness, and acquire again right purpose of heart by readings, vigils, constant prayer, and the loneliness of solitude, and get patience by endurance of hardships; that we should serve our Maker amid blasphemies and reproaches, and follow truth at the cost of the hatred of this world, and its hostility, if need be.
~St John Cassian (Conference with Abbot Daniel)
Prayerful Life 