Christ Jesus our Lord (may He bear with me a moment in thus expressing myself!), whosoever He is, of what God soever He is the Son, of what substance soever He is man and God, of what faith soever He is the teacher, of what reward soever He is the Promiser, did, whilst He lived on earth, Himself declare what He was, what He had been, what the Father’s will was which He was administering, what the duty of man was which He was prescribing; (and this declaration He made,) either openly to the people, or privately to His disciples, of whom He had chosen the twelve chief ones to be at His side, and whom He destined to be the teachers of the nations.
Tertullian
Against Marcion
The Prescription Against Heretics
Chapter XX