John Calvin Commentary 1 Thessalonians 4:10

"for indeed ye do it toward all the brethren that are in all Macedonia. But we exhort you, brethren, that ye abound more and more;" — 1 Thessalonians 4:10 (ASV)

And we exhort you. Though he declares that they were sufficiently prepared by themselves for all acts of love, he nevertheless does not cease to exhort them to make progress, since perfection is not found in human beings. And, unquestionably, whatever appears in us in a high state of excellence, we must still desire for it to become better.

Some connect the verb φιλοτιμεῖσθαι with what follows, as if he exhorted them to strive to maintain peace; but it corresponds better with the preceding expression. For after having admonished them to increase in love, he recommends to them a sacred emulation, so that they might strive among themselves in mutual affection, or at least he instructs that each one strive to conquer himself; and I rather adopt this latter interpretation.

Therefore, so that their love may be perfect, he requires that there be a striving among them, such as is usually found on the part of those who eagerly aspire to victory. This is the best emulation, when each one strives to overcome himself in doing good.

As for my not subscribing to the opinion of those who translate the words as strive to maintain peace, this single reason appears to me sufficiently valid: Paul would not have commanded such an arduous conflict for a matter of less difficulty—indeed, such a conflict is admirably well suited to advancement in love, where so many hindrances arise.

Nor would I have any objection to the other meaning of the verb—that they should exercise generosity generally towards others.