John Calvin Commentary Galatians 5:13

"For ye, brethren, were called for freedom; only [use] not your freedom for an occasion to the flesh, but through love be servants one to another." — Galatians 5:13 (ASV)

You have been called to liberty. He now proceeds to show how liberty must be used. In expounding the First Epistle to the Corinthians, we have pointed out that liberty is one thing, and its use is another. Liberty lies in the conscience and looks to God; its use lies in outward matters and deals not only with God but also with people.

Having urged the Galatians to allow no reduction of their liberty, he now instructs them to be moderate in its use. He lays down as a rule for its lawful use that it must not be turned into a pretext or occasion for licentiousness. Liberty is not granted to the flesh, which should rather be held captive under the yoke, but is a spiritual benefit that only pious minds are capable of enjoying.

But by love. The method explained here for restraining liberty from breaking out into wide and licentious abuse is to have it regulated by love. Let us always remember that the present question is not how we are free before God, but how we may use our liberty in our interactions with others. A good conscience submits to no slavery; but to practice outward servitude, or to abstain from using our liberty, poses no danger. In a word, if by love we serve one another, we will always aim for edification, so that we do not become self-indulgent, but use the grace of God for His honor and the salvation of our neighbors.