Exodus 4:8

8.And it shall come to pass, if they will not believe thee. In these words God took away from Moses every handle for doubt; as much as to say, that he was sufficiently provided and strengthened to overcome the stubbornness of the people; and yet, heaping up the measure to overflowing, he afterwards added a third sign, from whence Moses might attain full confidence, and that no further hinderance should oppose his pious desires. This, too, is a remarkable evidence of the kindness of God, that he deigned so liberally to add sign to sign, and to contend with the evil heart of the people, until with a strong hand he drew them out of their torpor of incredulity. Surely, if they neglected the first miracle, they were unworthy to have another proof of his power set before them by God. It was, then, a wonderful exercise of longsuffering still to persevere in arresting their dullness. With equal clemency does He now overlook our sluggishness of heart; because, when with far less reverence than we ought we receive the testimonies whereby He manifests His grace, He avenges not our foul ingratitude, but rather adds new remedies for the cure of our unbelief. As by the two former miracles God shewed the power which he willed to exercise by the hand of Moses, so in this third He taught them what would be His dealings with the Egyptians. And then, both from within and from without, Moses was confirmed before all the people. The conclusion is, then, that when God should lift up His hand against the Egyptians, so far would they be from having strength to resist, that the very strongholds in which they proudly trusted should be felt to be adverse and injurious to them. We know how many and various were the advantages they derived from the Nile. Their land, on one side, was rendered, by its opposing barrier, safe and invincible; its many ports enriched their nation by their convenience for the importation and exportation of merchandise; the fertility of their fields arose from its inundations; in a word, Egypt attributed the chief part of its prosperity to the Nile. But now God gives warning not only that it should not profit the Egyptians, but that it was in His power to turn all its advantages into injuries; nay, that the very stream which used to fertilize their land by its irrigation, should cover and defile it with blood. With respect to the words, the “voice of the sign” is figuratively applied to mean a demonstration of the power of God, by which the Israelites might be taught that Moses was sent them by God as their deliverer. For although the rod turned into a serpent could not speak, yet very loudly, indeed, did it announce, that what the Israelites deemed altogether impossible, would not be difficult to God. Others thus resolve the particle את, (51) “If they will not believe your voice, because of the sign;” but the former interpretation is more correct. The meaning of the expression, however, is added soon afterwards, in this distinction — “If they will not believe also these two signs, neither hearken unto thy voice;” as though God had said, that His power cried out, or thundered in His miracles, to obtain a hearing for the teaching of His servant.