Exodus 14

The Lord tells Moses to tell the people to camp by the sea.  He also tells Moses that Pharaoh will come after them and that the Lord will harden Pharaoh's heart.  Ultimately, God will get glory for all this and "the Egyptians shall know that I am the Lord".

So, Pharaoh and 600 chosen chariots and all the other chariots of Egypt come after Israel.  The Israelites see them and are afraid, but Moses encourages them, "Fear not, stand firm, and see the salvation of the Lord, which he will work for you today. For the Egyptians whom you see today, you shall never see again. The Lord will fight for you, and you have only to be silent".  They wont see them again, the Lord will fight for them.  I like what he says last, "and you have only to be silent".  They don't have to really do anything, they just have to sit back and watch quietly.  God will take care of it.

The angel of God moves behind them between the Egyptians and the Israelites, keeping them separated.  The sea is parted and they walk on dry ground with a wall of water on both their right and their left.  Well, the Egyptians foolishly go in after them and God even "threw the Egyptian forces into a panic, 25 clogging[b] their chariot wheels so that they drove heavily".  It isn't until then that they say “Let us flee from before Israel, for the Lord fights for them against the Egyptians".  Why didn't they say this earlier?

Well, the sea returns to normal and the Egyptians are killed.  This chapter ends well, "Thus the Lord saved Israel that day from the hand of the Egyptians, and Israel saw the Egyptians dead on the seashore. Israel saw the great power that the Lord used against the Egyptians, so the people feared the Lord, and they believed in the Lord and in his servant Moses"