Exodus 8:22

I will sever. A new feature is introduced, which distinguishes the later from earlier plagues, with one possible exception (see on Exodus 7:24). This constituted an additional evidence of the miraculous character of the visitations, well calculated to impress thoughtful and honest minds that God was not a local or even a national deity but one whose power extended to all peoples. Egyptians who studied the course of events during those fateful weeks or months must have recognized the supreme authority of Israel’s God over Egypt as well as over the Hebrews themselves.