After about 40 more years, God spoke to Moses from a bush that was on fire but didn't burn. God sent Moses back to Egypt to lead the Hebrews out of slavery, and into the land promised to Abraham. God demonstrated His power to Moses and revealed to Him His holy Name "YHVH" or "Yaweh" (Jehovah became a popular pronunciation in the 16th century through German translators although there is no "J" sound in the Hebrew).
God anointed Aaron to go with Moses to be the spokesman and they persuaded the people of Israel to follow them but Pharaoh would not let them go. Then God sent 10 devastating plagues on the Egyptians, the last plague being the death of the firstborn in every home whose doors were not marked with blood.
First Plague: Blood
Second Plague: Frogs
Third Plague: Lice
Fourth Plague: Flies
Fifth Plague: Disease on Livestock
Sixth Plague: Boils
Seventh Plague: Hail
Eighth Plague: Locusts
Ninth Plague: Darkness
Tenth Plague: Death of the First-Born
God commanded the Israelites to celebrate yearly the "Passover", where the death angel passed over the houses that had the blood of a lamb.
Exod 12:1-14 Now the LORD spoke to Moses and Aaron in the land of Egypt, saying, "This month shall be your beginning of months; it shall be the first month of the year to you. "Speak to all the congregation of Israel, saying: 'On the tenth day of this month every man shall take for himself a lamb, according to the house of his father, a lamb for a household. 'And if the household is too small for the lamb, let him and his neighbor next to his house take it according to the number of the persons; according to each man's need you shall make your count for the lamb. 'Your lamb shall be without blemish, a male of the first year. You may take it from the sheep or from the goats.
'Now you shall keep it until the fourteenth day of the same month. Then the whole assembly of the congregation of Israel shall kill it at twilight. 'And they shall take some of the blood and put it on the two doorposts and on the lintel of the houses where they eat it. 'Then they shall eat the flesh on that night; roasted in fire, with unleavened bread and with bitter herbs they shall eat it. . . roasted in fire . . . 'You shall let none of it remain until morning, and what remains of it until morning you shall burn with fire.
'And thus you shall eat it: with a belt on your waist, your sandals on your feet, and your staff in your hand. So you shall eat it in haste. It is the LORD'S Passover. 'For I will pass through the land of Egypt on that night, and will strike all the firstborn in the land of Egypt, both man and beast; and against all the gods of Egypt I will execute judgment: I am the LORD. 'Now the blood shall be a sign for you on the houses where you are. And when I see the blood, I will pass over you; and the plague shall not be on you to destroy you when I strike the land of Egypt. 'So this day shall be to you a memorial; and you shall keep it as a feast to the LORD throughout your generations.
After this Pharaoh finally gave in and agreed to let Israel go (and with all the wealth of Egypt), but as soon as they left, Pharaoh changed his mind. He sent his army after them where Israel was cornered against the Red Sea. God parted the waters and led them through on dry ground.
Exod 14:21-22 Then 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 into dry land, and the waters were divided. So the children of Israel went into the midst of the sea on the dry ground, and the waters were a wall to them on their right hand and on their left.