Thou didst blow with thy wind - Notice the solemn majesty of these few words, in immediate contrast with the tumult and confusion of the preceding verse. In Exodus 14:28, we read only, "the waters returned," here we are told that it was because the wind blew. A sudden change in the direction of the wind would bring back at once the masses of water heaped up on the north.
They sank as lead - See the note at Exodus 15:5.

Thou didst blow with thy wind,.... A strong east wind, Exodus 14:22 which is the Lord Christ's, who has it in his treasury, holds it in his fists, sends it out as he pleases, and it fulfils his word and will:
the sea covered them; which stood up in an heap as a wall to let Israel pass through, and fell down with all its waves and billows with great force upon the Egyptians, and covered and drowned them:
they sunk as lead in the mighty waters; which is a very heavy metal, and, being cast into the water, sinks to the bottom at once, as did the Egyptians in the Red sea, and as Babylon the great will, and never rise more, Revelation 18:21.

"Thou didst blow with Thy breath: the sea covered them, they sank as lead in the mighty waters." One breath of God was sufficient to sink the proud foe in the waves of the sea. The waters are called אדּרים, because of the mighty proof of the Creator's glory which is furnished by the waves as they rush majestically along.