They became serpents; either,
1. In appearance. For the Scripture oft speaks of things otherwise than they are, because they seem to be so. And therefore as the devil appearing to Saul in the likeness of Samuel is called Samuel; so may these rods upon the same account be called serpents, because through diabolical illusion they seemed to be so. Or,
2. Really, in manner expressed, Exodus 7:11. Aaron's rod swallowed up their rods; by which it was evident, either that Aaron's rod was turned into a real serpent, because it had the real properties and effects of a serpent, viz. to devour; or, at least, that the God of Israel was infinitely more powerful than the Egyptian idols or devils.