By this giving and receiving of honour, then, all are one. But I do not yet apprehend in what way this makes all one. Our Lord, however, explains the gradation and order in the consummating of this unity, when He adds, I in them, and Thou in Me; so that inasmuch as He was in the Father by His divine nature, we in Him by His incarnation, and He again in us by the mystery of the sacrament, a perfect union by means of a Mediator was established.
Reproduced in full. Translation: Oxford 1841 (Newman), public domain (Public domain).
Also cites: viii. de Trin