1 Corinthians 7:20 - Coke's Commentary on the Holy Bible

Let every man abide in the same calling, &c.— It is plain from what immediately follows, that this is not an absolute command; but only signifies, that a man should not think himself discharged by the privilege of his Christian state, and the franchises of the kingdom of Christ into which he was entered, from any ties or obligations that he was under as a member of the civil society. The thinking themselves freed by Christianity from those ties, was a fault, it seems, which those Christians at Corinth were very apt to run into; for St. Paul thinks it necessary to guard them against this prejudice three times in the compass of seven verses; and, in the form of a direct command, enjoins them not to change their conditionor state of life: whereby he manifestly intends that they should not change, upon a presumption that Christianity gave them a new or peculiar liberty to do so; for, notwithstanding the Apostle's positively bidding them to remain in the same condition in which they were at their conversion, it is yet certain, that it was lawful for them, as well as others, to change, where it was lawful for them to change had they not been Christians. See Lock