Philo Judaeus De Opificio Mundi 72

And he would not err who should raise the question why Moses attributed the creation of man alone not to one creator, as he did that of other animals, but to several. For he introduces the Father of the universe using this language: Let us make man after our image, and in our likeness. Had he then, shall I say, need of any one whatever to help him, He to whom all things are subject? Or, when he was making the heaven and the earth and the sea, was he in need of no one to co-operate with him; and yet was he unable himself by his own power to make man an animal so short-lived and so exposed to the assaults of fate without the assistance of others? It is plain that the real cause of his so acting is known to God alone, but one which to a reasonable conjecture appears probable and credible, I think I should not conceal; and it is this.