Galatians 5:13

In the latter part of this chapter the apostle comes to exhort these Christians to serious practical godliness, as the best antidote against the snares of the false teachers. Two things especially he presses upon them: - I. That they should not strive with one another, but love one another. He tells them (Gal 5:13) that they had been called unto liberty, and he would have them to stand fast in the liberty wherewith Christ had made them free; but yet he would have them be very careful that they did not use this liberty as an occasion to the flesh - that they did not thence take occasion to indulge themselves in any corrupt affections and practices, and particularly such as might create distance and disaffection, and be the ground of quarrels and contentions among them: but, on the contrary, he would have them by love to serve one another, to maintain that mutual love and affection which, notwithstanding any minor differences there might be among them, would dispose them to all those offices of respect and kindness to each other which the Christian religion obliged them to. Note, 1.

— Matthew Henry's Concise Commentary (public domain)

The "ye" is emphatical, from its position in the Greek, "Ye brethren"; as opposed to those legalists "who trouble you." unto liberty--The Greek expresses, "on a footing of liberty." The state or condition in which ye have been called to salvation, is one of liberty. Gospel liberty consists in three things, freedom from the Mosaic yoke, from sin, and from slavish fear. only, &c.--Translate, "Only turn not your liberty into an occasion for the flesh." Do not give the flesh the handle or pretext (Rom 7:8, "occasion") for its indulgence which it eagerly seeks for; do not let it make Christian "liberty" its pretext for indulgence (Gal 5:16-17; Pe1 2:16; Pe2 2:19; Jde 1:4). but by love serve one another--Greek, "Be servants (be in bondage) to one another." If ye must be servants, then be servants to one another in love. While free as to legalism, be bound by Love (the article in the Greek personifies love in the abstract) to serve one another (Co1 9:19). Here he hints at their unloving strifes springing out of lust of power. "For the lust of power is the mother of heresies" [CHRYSOSTOM].

— Jamieson-Fausset-Brown Commentary (public domain)