Cyril of Alexandria : He says, "I AM your God." This "I AM" means "I am the beginning." He explained all this to the all-wise Moses saying "I am the one who is." For he as Lord is truly the God of everything. Those things that are brought into being by him are said to be "beings" also and to share in the source of being.… Again he works in them a steadfast thinking and a well-established mind that they can see God to be truly existing in nature. To these he reveals his glory so that they are not carried away by deceitful voices. — COMMENTARY ON Isaiah 4:3.48:17-19 Jerome : (Verse 17, 18 and following) Thus says the Lord, your holy Redeemer, the God of Israel: I am the Lord your God, teaching you what is profitable, leading you in the way you should go. Oh, that you had paid attention to my commandments! Then your peace would have been like a river, and your righteousness like the waves of the sea. Your descendants would have been like sand, and the offspring of your womb like its grains; their name would never be cut off or destroyed from before me. Because God has promised future blessings to Israel, he explains why he afflicted them before. If they avoid the same mistakes, they will not suffer similar consequences. Yes, he said, if you had followed my commands: as the Seventy translated; or at least, with a desire for it, if you had followed my commands: if you had done so, your peace would have been like a river, and your righteousness like the waves of the sea, signifying abundance of all things. And what follows: and your offspring would have been like the sand, and the descendants of your womb like its grains: indeed, it seems to remain in the Jewish people, who to this day, like worms, produce children and grandchildren; but how is this to be understood in terms of the promise, when they do not have peace and righteousness? For either he is angry with them, or appeased. If he is angry, how is his seed multiplied every day? If he is appeased, how do they serve and not possess peace and justice? From this it is clear that it is said now of the apostolic seed, of which we also read above (In Chapter I): Unless the Lord of hosts had left us seed, we would have become like Sodom. And because it seems at that time not to have been fulfilled, it is fulfilled in the coming of Christ: and before his face the seed of Israel remains. — Commentary on Isaiah