1 Timothy 6:6

From the mention of the abuse which some put upon religion, making it to serve their secular advantages, the apostle, I. Takes occasion to show the excellency of contentment and the evil of covetousness. 1. The excellency of contentment, Ti1 6:6-8. Some account Christianity an advantageous profession for this world. In the sense they mean this is false; yet it is undoubtedly true that, though Christianity is the worst trade, it is the best calling in the world. Those that make a trade of it, merely to serve their turn for this world, will be disappointed, and find it a sorry trade; but those that mind it as their calling, and make a business of it, will find it a gainful calling, for it has the promise of the life that now is, as well as of that which is to come. (1.) The truth he lays down is that godliness with contentment is great gain. Some read it, godliness with a competency; that is, if a man have but a little in this world, yet, if he have but enough to carry him through it, he needs desire no more, his godliness with that will be his great gain. For a little which a righteous man has is better than the riches of many wicked, Psa 37:16.

— Matthew Henry's Concise Commentary (public domain)

But--Though they err in this, there is a sense in which "piety is" not merely gain, but "great means of gain": not the gaining which they pursue, and which makes men to be discontented with their present possessions, and to use religion as "a cloak of covetousness" (Th1 2:5) and means of earthly gain, but the present and eternal gain which piety, whose accompaniment is contentment, secures to the soul. WIESINGER remarks that Paul observed in Timothy a tendency to indolence and shrinking from the conflict, whence he felt (Ti1 6:11) that Timothy needed cautioning against such temptation; compare also the second Epistle. Not merely contentment is great gain (a sentiment of the heathen CICERO [Paradox 6], "the greatest and surest riches"), but "piety with contentment"; for piety not only feels no need of what it has not, but also has that which exalts it above what it has not [WIESINGER]. The Greek for contentment is translated "sufficiency" (Co2 9:8). But the adjective (Phi 4:11) "content"; literally, "having a sufficiency in one's self" independent of others. "The Lord always supplies His people with what is necessary for them. True happiness lies in piety, but this sufficiency [supplied by God, with which moreover His people are content] is thrown into the scale as a kind of overweight" [CALVIN] (1Ki. 17:1-16; Psa 37:19; Isa 33:6, Isa 33:16; Jer 37:21).

— Jamieson-Fausset-Brown Commentary (public domain)