1 In the preceding lesson of the holy Gospel, which is followed by the one that has just been read, the Lord Jesus had said that He and the Father would come to those who loved Them, and make Their abode with them. But He had also already said above of the Holy Spirit, “But you shall know Him; for He shall dwell with you, and shall be in you”: by which we understood that the divine Trinity dwells together in the saints as in His own temple. But now He says, “These things have I spoken unto you while [still] dwelling with you.” That dwelling, therefore, which He promised in the future, is of one kind; and this, which He declares to be present, is of another. The one is spiritual, and is realized inwardly by the mind; the other is corporal, and is exhibited outwardly to the eye and the ear. The one brings eternal blessedness to those who have been delivered, the other pays its visits in time to those who await deliverance. As regards the one, the Lord never withdraws from those who love Him; as regards the other, He comes and goes. These things, He says, “have I spoken unto you, while [still] dwelling with you;” that is, in His bodily presence, wherein He was visibly conversing with them.
2. “But the Comfort,” He adds, “[which is] the Holy Ghost, whom the Father will send in my name, He shall teach you all things, and bring all things to your remembrance, whatsoever I have said unto you.” Is it, then, that the Son speaks, and the Holy Spirit teaches, so that we merely get hold of the words that are uttered by the Son, and then understand them by the teaching of the Spirit as if the Son could speak without the Holy Spirit, or the Holy Spirit teach without the Son: or is it not rather that the Son also teaches and the Spirit speaks, and, when it is God that speaks and teaches anything, that the Trinity itself is speaking and teaching? And just because it is a Trinity, its persons required to be introduced individually, so that we might hear it in its distinct personality, and understand its inseparable nature. Listen to the Father speaking in the passage where you read, “The Lord said unto me, You are my Son:” listen to Him also teaching, in that where you read, “Every man that has heard, and has learned of the Father, comes unto me.” The Son, on the other hand, you have just heard speaking; for He says of Himself, “Whatsoever I have said unto you:” and if you would also know Him as a Teacher, bethink yourself of the Master, when He says, “One is your Master, even Christ.” Furthermore, of the Holy Spirit, whom you have just been told of as a Teacher in the words, “He shall teach you all things,” listen to Him also speaking, where you read in the Acts of the Apostles, that the Holy Spirit said to the blessed Peter, “Go with them, for I have sent them.” The whole Trinity, therefore, both speaks and teaches: but were it not also brought before us in its individual personality, it would certainly altogether surpass the power of human weakness to comprehend it. For as it is altogether inseparable in itself, it could never be known as the Trinity, were it always spoken of inseparably; for when we speak of the Father, and the Son, and the Holy Spirit, we certainly do not pronounce them simultaneously, and yet in themselves they cannot be else than simultaneous. But when He added, “He will bring to your remembrance,” we ought also to understand that we are commanded not to forget that these pre-eminently salutary admonitions are part of that grace which the Holy Spirit brings to our remembrance.
3. “Peace,” He said, “I leave with you, my peace I give unto you.” It is here we read in the prophet, “Peace upon peace:” peace He leaves with us when going away, His own peace He will give us when He comes in the end. Peace He leaves with us in this world, His own peace He will give us in the world to come. His own peace He leaves with us, and abiding therein we conquer the enemy. His own peace He will give us when, with no more enemies to fight, we shall reign as kings. Peace He leaves with us, that here also we may love one another: His own peace will He give us, where we shall be beyond the possibility of dissension. Peace He leaves with us, that we may not judge one another of what is secret to each, while here on earth: His own peace will He give us, when He “will make manifest the counsels of the heart; and then shall every man have praise of God.” And yet in Him and from Him it is that we have peace, whether that which He leaves with us when going to the Father, or that which He will give us when we ourselves are brought by Him to the Father. And what is it He leaves with us, when ascending from us, save His own presence, which He never withdraws? For He Himself is our peace who has made both one. It is He, therefore, that becomes our peace, both when we believe that He is, and when we see Him as He is. For if, so long as we are in this corruptible body that burdens the soul, and are walking by faith, not by sight, He forsakes not those who are sojourning at a distance from Himself; how much more, when we have attained to that sight, shall He fill us with Himself?
Source: Tractates on the Gospel of John (New Advent)