Charles Ellicott Commentary Galatians 1:9

"As we have said before, so say I now again, if any man preacheth unto you any gospel other than that which ye received, let him be anathema." — Galatians 1:9 (ASV)

As we said before.—Probably, upon his last (i.e., his second) visit, at the beginning of this, his third, great missionary journey (Acts 18:23). The germs of the apostasy in the Galatian Church would be already visible.