He put forth his hand.--Faith triumphed over instinct. Moses had "fled from" the snake when first he saw it (Exodus 4:3). Now he is daring enough to stoop down, put his hand on the creature's tail, and so lift it up.
It became a rod.--Its real nature returned to it. Once more it was, not a stiffened serpent, but an actual staff, or walking-stick.
and he put forth his hand, and caught it, and it became a rod in his hand; as it was before. Some think this refers to the threefold state of the Israelites, first to their flourishing estate under Joseph, when they were as a rod or staff, then to their dejected state, by this rod cast to the ground, and become a serpent, and lastly to their restoration and liberty, by its becoming a rod again: others refer it to Christ, who is the power of God, and the rod of his strength, and who in his state of humiliation was like this rod, cast to the ground and became a serpent, of which the brazen serpent was a type, and who by his resurrection from the dead regained his former power; but perhaps they may be most right who think it refers to the service and ministry of Moses, which seemed terrible to him at first, like a hurtful serpent, from which he fled; but after he was confirmed by the word of God, he readily undertook it.
(l) De Vita Mosis, l. 1. 614.