Those aspiring to the state of virtue must strive to fulfill the commandments by sustaining this inward struggle, travail and meditation unceasingly night and day, whether praying or serving, eating or drinking, or doing anything else. In this way, if any good comes about it will be to God’s glory and not to their own. The fulfillment of the commandments presents no difficulty or trouble to us when it is facilitated by the love of God and when this love relieves it of all that is burdensome. As has been said, the whole effort of the enemy is directed towards distracting the intellect from the remembrance, fear and love of God, and to turning it by means of earthly forms and seductions away from what is truly good towards what appears to be good.
-- St. Symeon Metaphrastis (d. 10th century), Paraphrase of the Homilies of St. Makarios of Egypt, 1.14