The magicians of Egypt did so. They could not do what Moses and Aaron had done—stretch out, that is, a rod over the Nile, and turn it and all its branches, and ponds, and pools, into blood, for this was already done.
They could only show their skill upon some small quantity of water in a cup or other vessel. No doubt they produced some apparent change, which was accepted by Pharaoh as an equivalent to what had been effected by the Israelite chiefs, but which must have fallen far short of it.
Pharaoh would not be a severe critic.