But overthrew Pharaoh and his host in the Red sea - Margin, as in Hebrew, shaked off. The word is applicable to a tree shaking off its foliage. Isaiah 33:9. The same word is used in Exodus 14:27 : "And the Lord overthrew (Margin, shook off) the Egyptians in the midst of the sea," He shook them off as if he would no longer protect them. He left them to perish.
For his mercy - Their destruction was done in mercy to his people and to the world, for it was the means of deliverance to Israel. The death of a wicked man is a benefit to the world, and the act of removing him may be really an act of the highest benevolence to mankind. No wrong is done to such people, for they deserve to die; and the only service which can be rendered to the world through them is by their removal from the earth.

But overthrew Pharaoh and his host in the Red sea,.... In the same sea which was parted for the Israelites, and through which they passed safely as on dry land; into which Pharaoh and his army entering in pursuit of them in their chariots, the Lord "shook" (u) him and them out of them, as the word signifies; and causing the waters to return and cover them; they were drowned in them, Exodus 14:28. This was an emblem of the destruction of Satan, and of his principalities and powers, by Christ, who thereby has saved his spiritual Israel out of their hands; and of the casting of the sins of God's people into the depths of the sea, never to be seen more, or to appear any more against them to their condemnation; and of the everlasting ruin and perdition of ungodly men;
for his mercy endureth for ever; it was in mercy to Israel that Pharaoh and his host were destroyed, who threatened them with ruin; and therefore they sung of judgment and of mercy, and gave thanks to God for this instance of his vengeance on their enemies, and of goodness to them, Exodus 15:1.
(u) "excussit", V. L. Pagninus, Montanus, Junius & Tremellius, Piscator, &c.

overthrew--literally, "shook off," as in Exodus 14:27, as a contemptuous rejection of a reptile.