And it shall come to pass, if they will not believe thee, neither hearken to the voice of the first sign, that they will believe the voice of the latter sign. If they will not believe - the voice of the first sign, etc. - Probably intimating that some would be more difficult to be persuaded than others: some would yield to the evidence of the first miracle; others would hesitate till they had seen the second; and others would not believe till they had seen the water of the Nile turned into blood, when poured upon the dry land; Exodus 4:9.
Related Commentaries of Exodus 4:8
Exodus 4:8
8 And it shall come to pass, if they will not believe thee, neither hearken to the voice of the first sign, that they will believe the voice of the latter sign.