The Exodus from The Land Of Goshen occurred on the First Day of Unleavened Bread.
"And Moses [see also The Education Of Moses] said to the people, "Remember this day, in which you came out from Egypt, out of the house of bondage, for by strength of hand The Lord brought you out from this place; no leavened bread shall be eaten. This day you are to go forth, in the month of Abib [see Bible Calendar and Bible Months].
"And Moses took the bones of Joseph with him; for Joseph had solemnly sworn the people of Israel, saying, "God will visit you; then you must carry my bones with you from here." (Exodus 13:19 RSV)
Although the Israelites were armed for battle, The Lord provided them with all of the "fire power" that they would need to defeat the powerful army that was about to attack them.
"But God led the people round by the way of the wilderness toward the Red Sea. And the people of Israel went up out of the land of Egypt equipped for battle." (Exodus 13:18 RSV)
Exodus Chapter 14
As had been the situation all through the plagues upon Egypt, once the pressure was decreased the Pharaoh's stubbornness returned.
"When the king of Egypt [see Egypt's Royal House] was told that the people had fled, the mind of Pharaoh and his servants was changed toward the people, and they said, "What is this we have done, that we have let Israel go from serving us?" So he made ready his chariot and took his army with him, and took six hundred picked chariots and all the other chariots of Egypt with officers over all of them. And The Lord hardened the heart of Pharaoh king of Egypt and he pursued the people of Israel as they went forth defiantly. The Egyptians pursued them, all Pharaoh's horses and chariots and his horsemen and his army, and overtook them encamped at the sea, by Piha-hiroth, in front of Baal-zephon." (Exodus 14:5-9 RSV)
With The Lord holding the Egyptian army back, the sea was "parted" by a strong east wind (see the Fact Finder question below). For the Israelites, it was a bridge to freedom; for the Egyptian army, it was an ambush.
"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." (Exodus 14:21-22 RSV)
Exodus Chapter 15
With the enemy army at the bottom of the sea, the Israelites sang for joy amidst their victory and their freedom.
"Then Moses and the people of Israel sang this song to The Lord, saying, "I will sing to The Lord, for He has triumphed gloriously; the horse and his rider He has thrown into the sea. The Lord is my strength and my song, and He has become my salvation; this is my God, and I will praise Him, my father's God, and I will exalt Him. The Lord is a man of war; The Lord is His Name [see Names Of God]. "Pharaoh's chariots and his host he cast into the sea; and his picked officers are sunk in the Red Sea. The floods cover them; they went down into the depths like a stone. Thy right hand, O Lord, glorious in power, thy right hand, O Lord, shatters the enemy." (Exodus 15:1-6 RSV)
The Lord reminded them however that with freedom comes responsibility and obedience; otherwise, people are merely "free" like rebellious Satan.
"There The Lord made for them a statute and an ordinance and there he proved them, saying, "If you will diligently hearken to the voice of The Lord your God, and do that which is right in his eyes, and give heed to his commandments and keep all his statutes, I will put none of the diseases upon you which I put upon the Egyptians; for I am The Lord, your healer."
Exodus Chapter 16
The Israelites had spent their lives being cared for by their slave masters. Freedom and personal responsibility were new to them, so they whined like children when they had to begin looking after themselves more.
"They set out from Elim, and all the congregation of the people of Israel came to the wilderness of Sin, which is between Elim and Sinai, on the fifteenth day of the second month after they had departed from the land of Egypt. And the whole congregation of the people of Israel murmured against Moses and Aaron in the wilderness, and said to them, "Would that we had died by the hand of The Lord in the land of Egypt, when we sat by the fleshpots and ate bread to the full; for you have brought us out into this wilderness to kill this whole assembly with hunger." (Exodus 16:1-3 RSV)
The Lord supplied them with manna (see also Christ, The Bread of Life) and quail.
"I have heard the murmurings of the people of Israel; say to them, 'At twilight you shall eat flesh, and in the morning you shall be filled with bread; then you shall know that I am The Lord your God.'"
The Israelites had not yet arrived at Mount Sinai where The Ten Commandments (see The Decalogue) were formally given, but they were already well aware of The Lord's Sabbath that has existed and been observed since creation (see The Ten Commandments Before Sinai? and Do We Have The Original Calendar?).
"On the sixth day they gathered twice as much bread, two omers apiece; and when all the leaders of the congregation came and told Moses, he said to them, "This is what The Lord has commanded: 'Tomorrow is a day of solemn rest, a holy Sabbath to The Lord; bake what you will bake and boil what you will boil, and all that is left over lay by to be kept till the morning.'"
Fact Finder: By what means did the sea actually part for the Israelites to cross? What sort of "walls" of water were on each side of them?