Guarding And Watching

Ἴσως ἀγνοεῖς, ἀδελφὲ, ὅτι ὁ νόμος τοῦ Θεοῦ τηρούμενος, τηρεῖν, καὶ φρουρεῖν, καὶ περισκέπειν πέφυκεν τοὺς τηρεῖν τοῦτον, καὶ φυλάττειν σὺν νήψει σπουδάζοντας. Ἅγιος Νειλος, Βιβλιον Πρῶτον, Ἐπιστολὴ ΡΝΖ' Θεογνωστος Source: Migne PG 79 148a

Perhaps you are ignorant, my brother, of the keeping of the law of God, that to keep is to protect, and to watch over those who keep it, and to guard it in a state of alert sobriety. Saint Nilus of Sinai, Book 1, Letter 157 To Theognostos