Cyril of Alexandria

But the way in which a man loses his life that he may save it, and how he who imagines that he is saving loses it, Paul clearly shows, where he says of the saints, "They that are Jesus Christ's have crucified the flesh, with its affections and lusts." For those who have really become true followers of Christ our common Saviour, crucify their flesh, and put it to death, by being constantly engaged in labours and struggles unto piety, and by mortifying its natural desire. …

Commentary On Luke, Homily 118 ↗

Theophylact of Ohrid

Then the Lord adds what also relates to the foregoing: "Whoever seeks to save his life shall lose it." Let no one, He says, during the persecution of the Antichrist try to save his life, for such a person shall lose it. But whoever gives himself over to death and to suffering in general shall be saved, not bowing before the tyrant out of love for life. …

Commentary on Luke ↗

Bede

Whoever seeks to save his life will lose it. This sentence can be correctly understood in two ways, but both meanings refer to one single end, namely, to suffer adversities for Christ, indeed not to fear to endure death itself. For he who, with death threatening from a persecutor, if he does not deny Christ, prefers rather to save his life for a time by denying, undoubtedly prepares it for eternal perdition. …

On the Gospel of Luke ↗

Bonaventure

Third, regarding the reason for the danger, he adds: Whoever shall seek to save his life, through private love; for soul is taken here for the carnal life, about which Leviticus 17: "The soul of all flesh is in the blood"; the Gloss there: "He called the life of the body soul — not the soul which departs from the body, but that which ends with death." He who loves it too much seeks to save this; whence the Gloss on whoever shall seek to save his life: "He who wishes to save his carnal life in the world by denying Christ." Concerning …

Commentary on Luke, Chapter 17 ↗