And Moses stretched out his hand over the sea; and the LORD caused the sea to go back by a strong east wind all that night, and made the sea dry land, and the waters were divided.

Wesley's Notes

14:21 We have here the history of that work of wonder which is so often mentioned both in the Old and New Testament. An instance of God's almighty power in dividing the sea, and opening a passage through the waters. It was a bay, or gulf, or arm of the sea, two or three leagues over. The God of nature has not tied himself to its laws, but when he pleases dispenseth with them, and then the fire doth not burn, nor the water flow. They went through the sea to the opposite shore; they walked upon dry land in the midst of the sea; and the pillar of cloud being their rereward, the waters were a wall to them on their right hand, and on their left. Moses and Aaron it is likely ventured first, into this untrodden path, and then all Israel after them; and this march through the paths of the great waters would make their march afterwards through the wilderness less formidable. This march through the sea was in the night, and not a moon - shine night, for it was seven days after the full moon, so that they had no light but what they had from the pillar of fire. This made it the more awful, but where God leads us, he will light us; while we follow his conduct we shall not want his comforts.

Jamieson-Fausset-Brown Bible Commentary

21. Moses stretched out his hand, &c.-The waving of the rod was of great importance on this occasion to give public attestation in the presence of the assembled Israelites, both to the character of Moses and the divine mission with which he was charged.

the Lord caused . a strong east wind all that night-Suppose a mere ebb tide caused by the wind, raising the water to a great height on one side, still as there was not only "dry land," but, according to the tenor of the sacred narrative, a wall on the right hand and on the left [Ex 14:22], it would be impossible on the hypothesis of such a natural cause to rear the wall on the other. The idea of divine interposition, therefore, is imperative; and, assuming the passage to have been made at Mount Attakah, or at the mouth of Wady Tawarik, an east wind would cut the sea in that line. The Hebrew word kedem, however, rendered in our translation, "east," means, in its primary signification, previous; so that this verse might, perhaps, be rendered, "the Lord caused the sea to go back by a strong previous wind all that night"; a rendering which would remove the difficulty of supposing the host of Israel marched over on the sand, in the teeth of a rushing column of wind, strong enough to heap up the waters as a wall on each side of a dry path, and give the intelligible narrative of divine interference.

Matthew Henry's Concise Commentary

14:21-31 The dividing the Red sea was the terror of the Canaanites, Jos 2:9; the praise and triumph of the Israelites, Ps 114:3; 106:9; 136:13. It was a type of baptism, 1Co 10:1,2. Israel's passage through it was typical of the conversion of souls, Isa 11:15; and the Egyptians being drowned in it was typical of the final ruin of all unrepenting sinners. God showed his almighty power, by opening a passage through the waters, some miles over. God can bring his people through the greatest difficulties, and force a way where he does not find it. It was an instance of his wonderful favour to his Israel. They went through the sea, they walked upon dry land in the midst of the sea. This was done, in order to encourage God's people in all ages to trust him in the greatest straits. What cannot he do who did this? What will not he do for those that fear and love him, who did this for these murmuring, unbelieving Israelites? Then followed the just and righteous wrath of God upon his and his people's enemies. The ruin of sinners is brought on by their own rage and presumption. They might have let Israel alone, and would not; now they would flee from the face of Israel, and cannot. Men will not be convinced, till it is too late, that those who meddle with God's people, meddle to their own hurt. Moses was ordered to stretch out his hand over the sea; the waters returned, and overwhelmed all the host of the Egyptians. Pharaoh and his servants, who had hardened one another in sin, now fell together, not one escaped. The Israelites saw the Egyptians dead upon the sands. The sight very much affected them. While men see God's works, and feel the benefit, they fear him and trust in him. How well were it for us, if we were always in as good a frame as sometimes! Behold the end to which a Christian may look forward. His enemies rage, and are mighty; but while he holds fast by God, he shall pass the waves in safety guarded by that very power of his Saviour, which shall come down on every spiritual foe. The enemies of his soul whom he hath seen to-day, he shall see no more for ever.