Bede : And God said to him: I am, and my covenant is with you. For what is it for the Lord to say: I am, if not to clearly declare the state of his eternity, in which he is always the same? About which the Psalm also says: But you are the same (Psalms 102:28). This place harmonizes with the Gospel where the Lord said to the Jews: Before Abraham was, I am (John 8:58). For appearing in the flesh, he taught that he himself was the one who had once appeared to Abraham in spirit, when he repeated to the Jews the same testimony of his essence that he had given to Abraham; but the Jews were troubled because they had heard: Before Abraham was, I am; yet Abraham rejoiced when he heard: I am, and did not doubt that God existed before he did; hence, because he faithfully heard the word of divine eternity, he received in the increase of reward that he would be called and be the father of many nations. Moreover, the Jews, because they could not grasp the mysteries of divinity they'd heard, were cast out from the lineage of Abraham, and were counted among the offspring of vipers: Finally, they took up stones to throw at him; but he hid himself from them, and went out of the temple (John 8:59), so that, evidently hidden from their stony hearts, and going out, he would come to reveal to the Gentiles the knowledge of his majesty. For even then having gone out of the temple, he restored sight to the man born blind. Evidently as a figure of grace, with which he was to enlighten the hearts of the Gentiles. It follows: — Commentary on Genesis (Hexaemeron) Jerome : (Chapter 17—Verse 3 and following) And the Lord spoke to him, saying: Behold, my covenant is with you, and you shall be the father of a multitude of nations. It should be noted that wherever we read Testament in Greek, in the Hebrew language it is the word covenant or pact, that is, Berith (). — Hebrew Questions on Genesis