John Cassian, On the Incarnation of the Lord, Against Nestorius VII.15: How Christ could be said by the Apostle to be without genealogy

How does he say that the Lord was “without genealogy,” when the Gospel of the Evangelist Matthew begins with the Saviour’s genealogy, saying: “The book of the generations of Jesus Christ, the Son of David, the Son of Abraham”? Therefore according to the Evangelist He has a genealogy, and according to the Apostle, He has not: for according to the Evangelist, He has it on the mother’s side, according to the Apostle He has not, as He springs from the Father. And so the Apostle well says: “Without father, without mother, without genealogy:” and where he lays down that He was begotten without mother, there also he records that He was without genealogy. And thus as regards both the nativities of the Lord, the writings of the Evangelist and of the Apostle agree together. For according to the Evangelist He has a genealogy “without father,” when born in the flesh: and according to the Apostle, the Lord has not, when begotten in His Divine nature “without mother;” as Isaiah says: “But who shall declare His generation?”