1 Corinthians 9:19-23

for being free from all men, to all men I made myself servant, that the more I might gain; and I became to the Jews as a Jew, that Jews I might gain; to those under law as under law, that those under law I might gain; to those without law, as without law — (not being without law to God, but within law to Christ) — that I might gain those without law; I became to the infirm as infirm, that the infirm I might gain; to all men I have become all things, that by all means I may save some. And this I do because of the good news, that a fellow-partaker of it I may become