Crossing the Red Sea
When Moses put his arm out at God's command, the waters of the Red Sea parted and were frozen in place on either side of some dry land. Moses crossed the sea in approx 1445BC with over 3 million people.
When they had crossed safely over, the water came back drowning the chasing Egyptian armies.
This was a continuation of miracles that God did as He brought His people the Israelites back to the land that He had promised them many centuries ago.
The Egyptians will know that I am the LORD and also the people feared the LORD and put their trust in him and in Moses his servant yet they still grumbled against Moses and God many times over the next 40 years.
Moses crosses the Red Sea
11 They said to Moses, "Was it because there were no graves in Egypt that you brought us to the desert to die? What have you done to us by bringing us out of Egypt? 12 Didn't we say to you in Egypt, ‘Leave us alone; let us serve the Egyptians'? It would have been better for us to serve the Egyptians than to die in the desert!"
13 Moses answered the people, "Do not be afraid. Stand firm and you will see the deliverance the LORD will bring you today. The Egyptians you see today you will never see again. 14 The LORD will fight for you; you need only to be still."
15 Then the LORD said to Moses, "Why are you crying out to me? Tell the Israelites to move on. 16 Raise your staff and stretch out your hand over the sea to divide the water so that the Israelites can go through the sea on dry ground. 17 I will harden the hearts of the Egyptians so that they will go in after them. And I will gain glory through Pharaoh and all his army, through his chariots and his horsemen. 18 The Egyptians will know that I am the LORD when I gain glory through Pharaoh, his chariots and his horsemen."
19 Then the angel of God, who had been traveling in front of Israel's army, withdrew and went behind them. The pillar of cloud also moved from in front and stood behind them, 20 coming between the armies of Egypt and Israel. Throughout the night the cloud brought darkness to the one side and light to the other side; so neither went near the other all night long.
21 Then Moses stretched out his hand over the sea, and all that night the LORD drove the sea back with a strong east wind and turned it into dry land. The waters were divided, 22 and the Israelites went through the sea on dry ground, with a wall of water on their right and on their left.and
29 But the Israelites went through the sea on dry ground, with a wall of water on their right and on their left. 30That day the LORD saved Israel from the hands of the Egyptians, and Israel saw the Egyptians lying dead on the shore. 31 And when the Israelites saw the great power the LORD displayed against the Egyptians, the people feared the LORD and put their trust in him and in Moses his servant.
Exodus 14:11-22 and 14:29-31
Where they crossed the Red Sea is an interesting point.
One commentator suggests it was across a 13km path in the Gulf of Akaba the western arm of the Red Sea so they could enter Midian (Arabia).
Mt Sinai, where Moses saw the burning bush, is also in Arabia. Egypt at this time extended control all the way to the Gulf of Akaba with military strongholds.