Mark the Ascetic - On the Spiritual Law 121-125

121. The trickster who works mischief in secret is a snake 'lying in wait on the road and biting the horse's heel' (Gen. 49:17. LXX).
122. If you praise your neighbor to one man and criticize him to another, you are the slave of self-esteem and jealousy. Through praise you try to hide your jealousy, through criticism to appear better than your neighbor.
123. Just as sheep and wolves cannot feed together, so a man cannot receive mercy if he tricks his neighbor.
124. He who secretly mingles his own wishes with spiritual counsel is an adulterer, as the Book of Proverbs indicates (cf Prov. 6:32-33); and because of his stupidity he suffers pain and dishonor. 125. Just as water and fire cannot be combined, so self -justification and humility exclude one another.