The Problem Of The Mind

Τοῖς μὲν κοσμικοῖς οἱ δαίμονες διὰ τῶν πραγμάτων μᾶλλον παλαίουσι͵ τοῖς δὲ μοναχοῖς ὡς ἐπὶ πλεῖστον διὰ τῶν λογισμῶν· πραγμάτων γὰρ διὰ τὴν ἐρημίαν ἐστέρηνται· καὶ ὅσον εὐκολώτερον τὸ κατὰ διάνοιαν ἁμαρτάνειν τοῦ κατ΄ἐνέργειαν͵ τοσοῦτον χαλεπώτερος καὶ ὁ κατὰ διάνοιαν πόλεμος τοῦ διὰ τῶν πραγμάτων συνισταμένου· εὐκίνητον γάρ τι πρᾶγμα ὁ νοῦς καὶ πρὸς τὰς ἀνόμους φαντασίας δυσκάθεκτον. Εὐάγριος ὁ Ποντικός, Ὁ Πρακτικός

The demons prefer to wrestle with the worldly by means of the things of the world, but with monks for the most part by means of thoughts, because those in the desert are deprived of the world. And in as much as it is easier to sin in the mind than to go to the deed, so more difficult is the war of the mind than that which comes about because of worldly things; for the mind is a thing easily moved and hard to rein in when confronted with impious ideas. Evagrius Ponticus, The Praktikos