Charles Ellicott Commentary Numbers 22:35

"And the angel of Jehovah said unto Balaam, Go with the men; but only the word that I shall speak unto thee, that thou shalt speak. So Balaam went with the princes of Balak." — Numbers 22:35 (ASV)

Go with the men: but only the word that I shall speak unto thee ... — The command contained in Numbers 22:20 is here repeated, and the unrighteous prophet is punished by being constrained to reap the fruit of his own perversity. It should be observed that here, as elsewhere, the angel who speaks to Balaam identifies himself with Him who sent him: The word that I shall speak unto thee, that thou shalt speak. (Compare to Numbers 22:20, where God Himself is represented as delivering to Balaam the same injunction.)