“For not every fair-seeming desire falls into the heart from God, but only that which is profitable*. It happens that a man desires good, but God does not help him therein; for a semblance of a good desire may also enter a man from the devil. It seems to the man that this [the good desire that came into his heart] is for his help, but often it is beyond his measure. The devil himself contrives this for the man’s detriment and compels him to seek a [apparently good] thing, although he has not yet attained to this mode [level, depth, quality] of life; or because it is alien to his monastic [or other] state; or because when he moves the man to accomplish his desire, it is not the right time to do so; or because the man has neither the knowledge nor the bodily strength sufficient for it; or because the present moment does not lend us a hand. The devil strives in every way under the guise of some good thing to trouble the man, or to harm his body, or to set a hidden snare in his mind.
“Howbeit, let us make constant prayer fervently, as I said, with respect to the good desire that arises within us, and let each of us say: ‘May Thy will be done, until I bring to completion the good work which I have desired to do, if it be pleasing to Thy will. For it is easy for me to will it, but to do it is not within my power, unless I receive grace from Thee; though in truth both are Thine, “both to will and to do” (Phil. 2:13). For it is not without Thy grace that I was either persuaded, or afraid, to accept this desire set in motion within me.’
“The habitual practice of the an who desires good in the discernment of his mind is this: in prayer to labor for it continually, and through prayer to receive power that aids him in doing it and wisdom to distinguish what is genuine from what is counterfeit. The good is discerned by much prayer, by toil and watchfulness, incessant yearning, constant tears and humility, and by assistance from Heaven, especially when a man has proud thoughts which oppose it; for these obstruct God’s help from us; but we bring them to naught by prayer.”
* So often, we think of the good as a (Christian) philosopher would rather than in terms of what will bring profit (spiritual, emotional, social, even biological) to specific people in specific settings at specific moments in history. We too easily crush the real, the immediate, the other in the name of a good. Unlike Jesus, we rush to extinguish the smouldering wick and cut off the bruised reed. Smoldering wicks are messy and far from ideal, but still contain a spark. St. Isaac warns us to be patient and prayerful lest we create real harm (to ourselves and others) in our rush to impose idealized good.