Of the truth then of the body and blood of Christ, no room for doubting remains: for, by the declaration of our Lord Himself, and by the teaching of our own faith, the flesh is really flesh, and the blood really blood. This then is our principle of life. While we are in the flesh, Christ dwelleth in us by His flesh. (c.14:19) And we shall live by Him, according as He liveth. If then we live naturally by partaking of Him according to the flesh, He also liveth naturally by the indwelling of the Father according to the Spirit. His birth did not give Him an alien or different nature from the Father.
Reproduced in full. Translation: Oxford 1841 (Newman), public domain (Public domain).
Also cites: vii. de Trin. c. 14