Origen

This may be understood in two ways. First thus; if any lover of this present life spares his life, fearing to die, and supposing that his life is ended with this death; he seeking in this way to save his life, shall lose it, estranging it from life eternal. But if any, despising the present life, shall contend for the truth unto death, he shall lose his life as far as this present life is concerned, but forasmuch as he loses it for Christ, he shall the more save it for life eternal. Otherwise thus; if any understand what is true salvation, and desire to obtain it for the salvation of his own life, he by denying himself loses his life as to the enjoyments of the flesh, but saves it by works of piety. He shews by saying. For he that will, that this passage must be connected in sense with that which went before. If then we understand the first, Let him deny himself, of the death of the body, we must take this that follows of death only; but if we understand the first of mortifying the propensities of the flesh, then, to lose his life, signifies to give up carnal pleasures.