John Gill 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 have said before, so say I now again Either when he first preached the Gospel among them; or rather referring to what he had just now said, which he repeats with some little alteration; as if any, men, or angels, be they of what name, figure, rank, or office whatever,

preach any other Gospel unto you, than that ye have received ; and as the apostle thought, readily, willingly, sincerely, and heartily, in the love of it; assenting to the truth, feeling the power of it, and openly professing it:

let him be accursed ; which he repeats, for the more solemn asseveration and confirmation of it; and to show that this did not drop from his lips hastily and inadvertently; nor did it proceed from any irregular passions, or was spoken by him in heat, and in an angry mood, his mind being ruffled, disturbed, and discomposed; but was said by him in the most serious and solemn manner, upon the most thoughtful and mature consideration of the affair.