He corroborates this statement by the authority of the old prophets.
But since up to this point we have made use more particularly of the witness, comparatively new, of evangelists and apostles, now let us bring forward the testimony of the old prophets, intermingling at times new things with old, that everybody may see that the holy Scriptures proclaim as it were with one mouth that Christ was to come in the flesh, with a body of His own complete. And so that far-famed and renowned prophet as richly endowed with Gods gifts as with his testimony, to whom alone it was given to be sanctified before His birth, 2472 Jeremiah, says, “This is our Lord, and there shall no other be accounted of in comparison with Him. He found out all the way of knowledge and gave it to Jacob His servant and Israel His beloved. Afterwards He was seen upon earth and conversed with men.” 2473 “This is,” then, he says, “our God.” You see how the prophet points to God as it were with his hand, and indicates Him as it were with his finger. “This is,” he says, “our God.” Tell me then, who was it that the prophet showed by these signs and tokens to be God? Surely it was not the Father? For what need was there that He should be pointed out, whom all believed that they knew? For even then the Jews were not ignorant of God, for they were living under Gods law. But he was clearly aiming at this, that they might come to know the Son of God as God. And so excellently did the Prophet say that He who had found out all knowledge, i.e., had given the law, was to be seen upon earth, i.e., was to come in the flesh, in order that, as the Jews did not doubt that He who had given the law was God, they might recognize that He who was to come in the flesh was God, especially since they heard that He, in whom they believed as God the giver of the law, was to be seen among men by taking upon Him manhood, as He Himself promises His own advent by the prophet: “For I myself that spoke, behold I am here.” 2474 “There shall then,” says the Scriptures, “be no other accounted of in comparison of Him.” Beautifully does the prophet here foresee false teaching, and so exclude the interpretations of heretical perverseness. “There shall no other be accounted of in comparison of Him.” For He is alone begotten to be God of God: at whose bidding the completion of the universe followed: whose will is the beginning of things: whose empire is the fabric of the world: who spake all things, and they came to pass: commanded all things, and they were created. He then alone it is who spake to the patriarchs, dwelt in the prophets, was conceived by the Spirit, born of the Virgin Mary, appeared in the world, lived among men, fastened to the wood of the cross the handwriting of our offences, triumphed in Himself, 2475 slew by His death the powers that were at enmity and hostile to us; and gave to all men belief in the resurrection, and by the glory of His body put an end to the corruption of mans flesh. You see then that all these belong to the Lord Jesus Christ alone: and therefore no other shall be accounted of in comparison with Him, for He alone is God begotten of God in this glory and unique blessedness. This then is what the prophets teaching was aiming at; viz., that He might be known by all men to be the only begotten Son of God the Father, and that when they heard that no other was accounted of as God in comparison with the Son, they might confess that there was but one God in the Persons of the Father and the Son. “After this,” he said, “He was seen upon earth and conversed with men.” You see how plainly this points to the advent and nativity of the Lord. For surely the Father—of whom we read that He can only be seen in the Son—was not seen upon earth, nor born in the flesh, nor conversed with men? Most certainly not. You see then that all this is spoken of the Son of God. For since the prophet said that God should be seen upon earth, and no other but the Son was seen upon earth, it is clear that the prophet said this only of Him, of whom facts afterwards proved that it was spoken. For when He said that God should be seen, He could not say this truly, except of Him who was indeed afterwards seen. But enough of this. Now let us turn to another point. “The labour of Egypt,” says the prophet Isaiah, “and the merchandise of Ethiopia and of the Sabæans, men of stature, shall come over to thee and shall be thy servants. They shall walk after thee, bound with manacles, and they shall worship thee, and they shall make supplication to thee: for in thee is God, and there is no God beside thee. For thou p. 579 art our God and we knew thee not, O God of Israel the Saviour.” 2476 How wonderfully consistent the Holy Scriptures always are! For the first mentioned prophet said, “This is our God,” and this one says, “Thou art our God.” In the one there is the teaching of Divinity, in the other the confession of men. The one exhibits the character of the Master teaching, the other that of the people confessing. For consider now the prophet Jeremiah daily teaching, as he does, in the church, and saying of the Lord Jesus Christ, “This is our God,” what else could the whole Church reply, as it does, than what the other prophet said to the Lord Jesus, “Thou art our God.” So that full well could the mention of their past ignorance be joined to their present acknowledgment, in the words of the people: “Thou art our God, and we knew thee not.” For well can these who, in times past being taken up with the superstitions of devils did not know God, yet when now converted to the faith say, “Thou art our God, and we knew thee not.”
Cf. Jer. i. 5.578:2473
The passage comes not from Jeremiah, but from Baruch 3.36-38. It is also quoted as from Jeremiah by Augustine (c. Faustin. xii. c. 43): and in the LXX. version the book of Baruch is placed among the works of Jeremiah, e.g., In both the Vatican and Alexandrine mss. they stand in the following order: (1) Jeremiah, (2) Baruch, (3) Lamentations, (4) the Epistle of Jeremy (Baruch c. vi. in A.V.). The passage which Cassian here quotes is constantly appealed to by both Greek and Latin Fathers, as a prophecy of the Incarnation. See e.g. S. Augustine (l.c.) S. Chrysost. “Ecloga” Hom. xxxiv. Rufinus in. Symb. § 5.578:2474
Isa. lii. 6.578:2475
Cf. Col. 2:14, 15.579:2476
Isa. 14:14, 15.