2 But if Christ did then [only] begin to have existence when He came [into the world] as man, and [if] the Father did remember [only] in the times of Tiberius Cæsar to provide for [the wants of] men, and His Word was shown to have not always coexisted with His creatures; [it may be remarked that] neither then was it necessary that another God should be proclaimed, but [rather] that the reasons for so great carelessness and neglect on His part should be made the subject of investigation.
For it is fitting that no such question should arise, and gather such strength, that it would indeed both change God, and destroy our faith in that Creator who supports us by means of His creation. For as we do direct our faith towards the Son, so also should we possess a firm and immoveable love towards the Father. In his book against Marcion, Justin does well say: “I would not have believed the Lord Himself, if He had announced any other than He who is our framer, maker, and nourisher. But because the only-begotten Son came to us from the one God, who both made this world and formed us, and contains and administers all things, summing up His own handiwork in Himself, my faith towards Him is steadfast, and my love to the Father immoveable, God bestowing both upon us.”
Source: Adversus haereses (New Advent)