Exodus 8:2-3. All thy borders — All the land that is within thy borders. And the river — Nile, under which are comprehended all other rivers, streams, and ponds, as appears from Exodus 8:5. But the Nile is particularly mentioned, because God would make that an instrument of their punishment and misery, in which they most gloried, (Ezekiel 29:3,) to which they gave divine honours, and which was the instrument of their cruelty against the Israelites, Exodus 1:22. Frogs shall go into thy bed-chamber — This plague was worse than the former, because it was more constant and more general: for the former in the waters did only molest them when they went to drink or use the water; but this troubled them in all places, and at all times, and annoyed all their senses with their filthy substance, shape, and noise, mingling themselves with their meats and drinks, and crawling into their beds, so that they could rest or be free from them nowhere. Into thine ovens — They shall come up in such swarms as even to enter the driest places, which they naturally shun.

8:1-15 Pharaoh is plagued with frogs; their vast numbers made them sore plagues to the Egyptians. God could have plagued Egypt with lions, or bears, or wolves, or with birds of prey, but he chose to do it by these despicable creatures. God, when he pleases, can arm the smallest parts of the creation against us. He thereby humbled Pharaoh. They should neither eat, nor drink, nor sleep in quiet; but wherever they were, they should be troubled by the frogs. God's curse upon a man will pursue him wherever he goes, and lie heavy upon him whatever he does. Pharaoh gave way under this plague. He promises that he will let the people go. Those who bid defiance to God and prayer, first or last, will be made to see their need of both. But when Pharaoh saw there was respite, he hardened his heart. Till the heart is renewed by the grace of God, the thoughts made by affliction do not abide; the convictions wear off, and the promises that were given are forgotten. Till the state of the air is changed, what thaws in the sun will freeze again in the shade.With frogs - Some months appear to have elapsed between this and the former plague, if the frogs made their appearance at the usual time, that is in September. The special species mentioned here is of Egyptian origin. This plague was, like the preceding, in general accordance with natural phenomena, but marvelous both for its extent and intensity, and for its direct connection with the words and acts of God's messengers. It had also apparently, like the other plagues, a direct bearing upon Egyptian superstitions. There was a female deity with a frog's head, and the frog was connected with the most ancient forms of nature-worship in Egypt. 2. I will smite all thy borders with frogs—Those animals, though the natural spawn of the river, and therefore objects familiar to the people, were on this occasion miraculously multiplied to an amazing extent, and it is probable that the ova of the frogs, which had been previously deposited in the mire and marshes, were miraculously brought to perfection at once. All thy land which is within thy borders; a synecdoche; so that word is used also Exodus 10:4,19 1 Kings 1:3 Psalm 147:14 Jeremiah 15:13. So the gate and the wall are put for the city to which they belong, Genesis 22:17 Amos 1:7,10,14.

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.

And if thou refuse to let them go, behold, I will smite all thy borders with {a} frogs:

(a) There is nothing so weak that God cannot use it to overcome the greatest power of man.