Jamieson, Fausset and Brown on Isaiah 44:8

8. be afraid--literally, "be astounded," or "distracted with fear."

from that time--namely, from the time that "I appointed the ancient people" (Is 44:7). From the time of Abraham's call, his family were the depositories of the predictions of the Redeemer, whereas the promise of Cyrus was not heard of till Isaiah's time; therefore, the event to the prediction and accomplishment of which God appeals in proof of His sole Godhead, is the redemption of man by a descendant of Abraham, in whose person "the ancient people" was first formally "appointed." The deliverance of the Jews, by Cyrus, is mentioned afterwards only as an earnest of that greater mercy [Horsley].

no God--Hebrew, tsur, "rock" (De 32:4); that is, a stronghold to take refuge in, and a solid foundation to build on.