John Calvin Commentary Matthew 10:39

"He that findeth his life shall lose it; and he that loseth his life for my sake shall find it." — Matthew 10:39 (ASV)

He who findeth his life. To prevent the former doctrine, which is very difficult and troublesome to the flesh, from having little weight with us, Christ confirms it in two ways by this statement. He affirms that people of excessive caution and foresight, when they consider themselves to have defended their life very well, will be disappointed and will lose it; and, on the other hand, that those who disregard their life will sustain no loss, for they will recover it.

We know that there is nothing people will not do or leave undone for the sake of life (so powerful is the attachment to it that is natural to us all); therefore, it was necessary for Christ to use such promises and threats in encouraging his followers to despise death.

To find the life here means to possess it, or to have it in safe keeping. Those who excessively desire an earthly life take pains to guard themselves against every kind of danger and flatter themselves with unfounded confidence, as if they were taking good care of themselves (Psalms 49:18). But their life, though defended by such powerful safeguards, will pass away, for they will at last die, and death will bring them everlasting ruin.

On the other hand, when believers surrender themselves to die, their soul, which appears to vanish in a moment, passes into a better life.

Yet, as people are sometimes found who carelessly lay down their lives, either for ambition or out of madness, Christ expressly states the reason why we should expose ourselves to death.

It is uncertain whether the discourse related by Luke was delivered on another occasion. There, too, our Lord exhorts his followers to bear the cross but does not dwell on it at equal length. To support this sentiment, he immediately adds two comparisons that Matthew does not mention, but since the subject discussed is substantially the same, I have not hesitated to introduce here what we find in Luke.