For when you do not deny that the Creator’s Son and Spirit and Substance is also His Christ, you must needs allow that those who have not acknowledged the Father have failed likewise to acknowledge the Son through the identity of their natural substance; for if in Its fulness It has baffled man’s understanding, much more has a portion of It, especially when partaking of the fulness.
Tertullian
The Five Books Against Marcion, Book III
Chapter VI