Jamieson, Fausset and Brown on 1 Corinthians 7:23

23. be not ye--Greek, "become not ye." Paul here changes from "thou" (1Co 7:21) to "ye." Ye all are "bought" with the blood of Christ, whatever be your earthly state (1Co 6:20). "Become not servants to men," either externally, or spiritually; the former sense applying to the free alone: the latter to Christian freemen and slaves alike, that they should not be servile adherents to their party leaders at Corinth (1Co 3:21, 22; Mt 23:8-10; 2Co 11:20); nor indeed slaves to men generally, so far as their condition admits. The external and internal conditions, so far as is attainable, should correspond, and the former be subservient to the latter (compare 1Co 7:21, 32-35).