Origen
Catena Aurea · Lukasevangelium 9
And he said to them all, If any man will come after me, let him deny himself, and take up his cross daily, and follow me. For whosoever will save his life shall lose it: but whosoever will lose his life for my sake, the same shall save it. For what is a man advantaged, if he gain the whole world, and lose himself, or be cast away? For whosoever shall be ashamed of me and of my words, of him shall the Son of man be ashamed, when he shall come in his own glory, and in his Father’s, and of the holy angels. But I tell you of a truth, there be some standing here, which shall not taste of death, till they see the kingdom of God.
(in Matt. tom. 12.) A man also denies himself when by a sufficient alteration of manners or a good conversation he changes a life of habitual wickedness. He who has long lived in lasciviousness, abandons his lustful self when he becomes chaste, and in like manner a forsaking of any crimes is a denial of one’s self.