Charles Ellicott Commentary Isaiah 43:10

"Ye are my witnesses, saith Jehovah, and my servant whom I have chosen; that ye may know and believe me, and understand that I am he: before me there was no God formed, neither shall there be after me." — Isaiah 43:10 (ASV)

You are my witnesses ... —These are collectively addressed as the servant of Jehovah. Their calling and election had not been cancelled, and they might yet fulfill it. They, in that restoration from exile which Isaiah had foretold, should be a living proof of the foresight granted to the prophets, and, therefore, of the foreknowledge of Him who alone could say, “I am He,” to whom past, present, and future were as one; and He, the Eternal, proclaims Himself as being also the only Savior.