Numbers 22:30-31 King James Version (KJV)
30 And the ass said unto Balaam, Am not I thine ass, upon which thou hast ridden ever since I was thine unto this day? was I ever wont to do so unto thee? and he said, Nay.
31 Then the Lord opened the eyes of Balaam, and he saw the angel of the Lord standing in the way, and his sword drawn in his hand: and he bowed down his head, and fell flat on his face.