Tertullian

“ If the number of the Trinity also offends you, as if it were not connected in the simple Unity, I ask you how it is possible for a Being who is merely and absolutely One and Singular, to speak in plural phrase, saying, “Let us make man in our own image, and after our own likeness;” ”

“ But there was One in whose image God was making man, that is to say, Christ’s image, who, being one day about to become Man (more surely and more truly so) , had already caused the man to be called His image, who was then going to be formed of clay—the image and similitude of the true and perfect Man. ”

“ In the following passage, however, “Behold the man is become as one of us,” [2] He is either deceiving or amusing us in speaking plurally, if He is One only and singular. Or was it to the angels that He spoke, as the Jews interpret the passage, because these also acknowledge not the Son? ”