Library Pseudo-Clement Clementine Homilies
Homily 16, Chapter 11: Genesis 1:26 appealed to by Simon
And Simon said: Since I see that you frequently speak of the God who created you, learn from me how you are impious even to him. For there are evidently two who created, as the Scripture says: 'And God said, Let us make man in our image, after our likeness.' Now 'let us make,' implies two or more; certainly not one only.
English translation in Ante-Nicene Fathers, Vol. VIII (eds. Alexander Roberts and James Donaldson; Buffalo: Christian Literature Publishing Co., 1886). Public domain. Digital text via New Advent Church Fathers.