Cainan, the son of Arphaxad, is a post-Flood patriarch named in the genealogy of Christ according to the flesh. He stands between Arphaxad and Salah in the line descending from Shem, the son of Noah, and is sometimes distinguished as the "second Cainan" to set him apart from the earlier Cainan, the son of Enos. The Orthodox Church commemorates him among the Holy Forefathers, the Old Testament ancestors of the Lord, on the Sunday before the Nativity of Christ, with a fixed commemoration on December 14.
His place in the genealogy rests on the Greek text of Scripture. The Septuagint translation of Genesis (11:12-13) inserts Cainan as a generation between Arphaxad and Salah, and the New Testament preserves the same reading in the genealogy of Jesus given by the Evangelist Luke (Luke 3:36). By tradition he is reckoned among the patriarchs of Mesopotamia in the age between Noah and Abraham; the record of his life is otherwise extremely sparse, the Scriptures naming him only within these genealogical lists.
A notable feature of this Forefather is textual. Cainan the son of Arphaxad does not appear in the Masoretic Hebrew text of Genesis, which names Arphaxad directly as the father of Salah without an intervening generation. He is likewise absent from the oldest Septuagint manuscripts and from the genealogical reckonings of several early Christian writers. The Orthodox liturgical tradition, following the Septuagint and the Lukan genealogy received in the Church, includes him among the righteous ancestors of Christ.