Exodus 8:18

Did so, i.e. endeavoured to do so. Thus to enter, Matthew 7:13, is put for striving to enter, Luke 13:24. Thus men are said to deliver, Genesis 37:21; to fight, Joshua 24:9; to return, Joshua 10:15; when they only attempted or endeavoured to do so. And therefore when it is said in any of the plagues that the magicians did so, it is not to be understood that they really did the same thing, but that they endeavoured to do so, and that they did something which looked like it. It was as easy for them to produce lice as frogs, but God hindered them, partly to confound them and their devilish arts, and to show that what they did before was only by his permission; and partly to convince Pharaoh and the Egyptians of their vanity in trusting to such impotent magicians, and in opposing that God who could control and confound them when he pleased.