The fact that God rescued Israel from the Egyptians is the main point of this story. The Israelites were freed from slavery! They crossed the Red Sea maybe in 1477 BC or perhaps 1250 BC. There are many theories as to when and how this happened or indeed whether it happened at all due to the lack of evidence apart from the Bible. David Pawson puts this well when he states that this event was such an embarrassment for Egypt that they never would have wanted to mention it again or keep any records. However, the crossing of the Red Sea has been celebrated by Jews for centuries in conjunction with the protection they received from the blood of the Passover lamb detailed in Exodus 12.
And the people of Israel journeyed from Rameses to Succoth, about six hundred thousand men on foot, besides women and children. A mixed multitude also went up with them, and very much livestock, both flocks and herds. Exodus 12:37-38, ESV.
Then in more detail the Crossing of the Red Sea as recorded in Exodus 14.
Then Moses stretched out his hand over the sea, and the Lord drove the sea back by a strong east wind all night and made the sea dry land, and the waters were divided. And the people of Israel went into the midst of the sea on dry ground, the waters being a wall to them on their right hand and on their left. The Egyptians pursued and went in after them into the midst of the sea, all Pharaoh’s horses, his chariots, and his horsemen. And in the morning watch the Lord in the pillar of fire and of cloud looked down on the Egyptian forces and threw the Egyptian forces into a panic, clogging their chariot wheels so that they drove heavily. And the Egyptians said, “Let us flee from before Israel, for the Lord fights for them against the Egyptians.”
Then the Lord said to Moses, “Stretch out your hand over the sea, that the water may come back upon the Egyptians, upon their chariots, and upon their horsemen.” So Moses stretched out his hand over the sea, and the sea returned to its normal course when the morning appeared. And as the Egyptians fled into it, the Lord threw the Egyptians into the midst of the sea. The waters returned and covered the chariots and the horsemen; of all the host of Pharaoh that had followed them into the sea, not one of them remained. But the people of Israel ewalked on dry ground through the sea, the waters being a wall to them on their right hand and on their left.
Thus the Lord saved Israel that day from the hand of the Egyptians, and Israel saw the Egyptians dead on the seashore. Israel saw th 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. Exodus 14:21-31, ESV.