And Trypho again inquired, “But if some one, knowing that this is so, after he recognizes that this man is Christ, and has believed in and obeys Him, wishes, however, to observe these [institutions], will he be saved?” I said, “In my opinion, Trypho, such an one will be saved, if he does not strive in every way to persuade other men, —I mean those Gentiles who have been circumcised from error by Christ, to observe the same things as himself, telling them that they will not be saved unless they do so. This you did yourself at the commencement of the discourse, when you declared that I would not be saved unless I observe these institutions.”
Justin Martyr
Dialogue with Trypho
Chapter XLVII