5 'A rash man and quite unskilled' (St. Leo the Great to Flavian, Ep . xxviii, I. Pl . liv, 755 s.), with an extremely obstinate disposition, Eutyches asserted that two moments of time should be distinguished: thus before the Incarnation there were two natures in Christ, the human and the divine; after their union, however, only one existed, since the Word had absorbed the human nature ( hominem ); the body of the Lord came from the Virgin Mary, but was not of our substance and matter; if, indeed, it was human, it was not consubstantial with us, nor with her who gave birth to Christ according to the flesh (cf. Flavian to St. Leo, Ep . xxvi; Pl . liv, 745). Therefore, it was not in true human nature that Christ was born, suffered, was fastened to the cross and rose from the tomb.
Source: Sempiternus Rex Christus (Vatican.va)