And if thou refuse to let them go,.... Will not obey the orders:
I will smite all thy borders with frogs; he gives him warning of the blow before he strikes, which shows his clemency and goodness, his patience and longsuffering; and this he did, not only that he might have time and space for repentance, and thereby avoid the blow; but that when it came, he might be sensible it was not by chance, or owing to second causes, but was from the Lord himself.
I will smite all thy borders with frogs: fill the whole land of Egypt with them, to the utmost borders thereof on every side. Some q say the word signifies a large Egyptian fish, which in the Arabic tongue is called Altamsach, that is, a crocodile, with which the Nile abounded; but such a creature could not invade and attack them in the manner as is after related.
q R. Chananeel apud Abendana, and some in Aben Ezra in Ioc.