And Justin well said in his book against Marcion, that he would not have believed the Lord Himself, if He had announced any other God than the Fashioner and Maker [of the world], and our Nourisher. But since, from the one God, who both made this world and formed us, and contains as well as administers all things, there came to us the only-begotten Son, summing up His own workmanship in Himself, my faith in Him is steadfast, and my love towards the Father is immoveable, God bestowing both upon us.— Irenæus: Heresies, iv. 6.
Source: Miscellaneous Fragments from Lost Writings (New Advent)