A serpent - This miracle had a meaning which Moses could not mistake. The serpent was probably the basilisk or Uraeus, the Cobra. This was the symbol of royal and divine power on the diadem of every Pharaoh. The conversion of the rod was not merely a portent, it was a sign, at once a pledge and representation of victory over the king and gods of Egypt!

A serpent - Of what sort we know not, as the word נחש nachash is a general name for serpents, and also means several other things, see Genesis 3:1 : but it was either of a kind that he had not seen before, or one that he knew to be dangerous; for it is said, he fled from before it. Some suppose the staff was changed into a crocodile; see Clarke on Exodus 7:10 (note).

And he said, cast it on the ground,.... That is, the rod or staff:

and he cast it on the ground, and it became a serpent; not in appearance only, but in reality, it was changed into a real living serpent; for God, who is the author of nature, can change the nature of things as he pleases; nor is it to be supposed that he would only make it look to the sight as if it was one, by working upon the fancy and imagination to think it was one, when it was not; no doubt but it was as really turned into a true serpent, as the water was turned really and truly into wine by our Lord; this was the first miracle that ever was wrought, that we know of. Dr. Lightfoot (h) observes, that as a serpent was the fittest emblem of the devil, Genesis 3:1 so was it a sign that Moses did not these miracles by the power of the devil, but had a power over and beyond him, when he could thus deal with the serpent at his pleasure, as to make his rod a serpent, and the serpent a rod, as he saw good:

and Moses fled from before it; the Jews say (i) it was a fiery serpent, but for this they have no warrant: however, without supposing that it might be terrible and frightful, inasmuch as a common serpent is very disagreeable to men, and such an uncommon and extraordinary one must be very surprising, to see a staff become a serpent, a living one, crawling and leaping about, and perhaps turning itself towards Moses, whose staff it had been. Philo the Jew (k) says, it was a dragon, an exceeding large one.

(h) Works, vol. 1. p. 702. (i) Pirke Eliezer, c. 40. (k) De Vita Mosls, l. 1. 614.

And he said, Cast it on the ground. And he cast it on the ground, and it became a serpent; and Moses fled from before it.

4:1-9 Moses objects, that the people would not take his word, unless he showed them some sign. God gives him power to work miracles. But those who are now employed to deliver God's messages to men, need not the power to work miracles: their character and their doctrines are to be tried by that word of God to which they appeal. These miracles especially referred to the miracles of the Lord Jesus Christ. It belonged to Him only, to cast the power of the devil out of the soul, and to heal the soul of the leprosy of sin; and so it was for Him first to cast the devil out of the body, and to heal the leprosy of the body.