Exodus Chapters 7-9
After Moses and his brother Aaron were unsuccessful in convincing the Pharaoh to release the Israelites from enslavement, the Lord empowered them to perform certain miracles and demonstrations to show the power of God.
The first action was when the rod was cast down in front of Pharaoh and it turned into a snake. The Pharaoh's magicians performed a trick converting their rods to snakes, but Moses' rod ate the other snakes.
Pharaoh refused to release the Israelites at Moses' demand to "Let My People Go". It is then that the Lord empowered Moses and Aaron to invoke a series of plagues upon Egypt. There were 10 subsequent plagues. There were three cycles of three-plagues each and then a final devastating plague to force the Pharaoh.
The first nine plagues came in three similar cycles. The cycle repeated itself after each third plague.
On the first, fourth and seventh plagues, the Lord had Moses warn Pharaoh early in the morning at the river's edge of the possibility of the plague. When those did not work to make Pharaoh give in, the second, fifth and eighth plagues came as a result of Moses' simple warning.
After Pharaoh refused to release the Israelites after the first two plagues of each cycle, the third plague of the cycle (third, sixth and ninth) came without warning to Pharaoh.
The first three plagues:
Blood: The first plague was when Aaron raised his rod at the river's edge as the Pharaoh watched. With a wave of the rod, the river was turned into blood, and subsequently all water in Egypt was turned into blood. The Pharaoh's magicians matched part of this change, but the plague lasted over Egypt for seven days. Exodus 7:25.
Frogs: The Lord sent Moses to Pharaoh to warn that if the Israelites were not released, the land would be smitten with frogs. Moses requested that Pharaoh let the people go to service the Lord. When Pharaoh refused, Aaron raised his hand and frogs came out of the river and overran the land, the houses, the people and the food. Exodus 8:2-6.
Pharaoh's magicians caused some frogs to appear and this helped harden Pharaoh's heart; however, the Pharaoh asked Moses and Aaron to get rid of the frogs and he would release the Israelites.
Moses appealed to the Lord and the Lord caused all the frogs to die except those in the river. The dead frogs piled up and died and created a tremendous smell.
When Pharaoh saw that he had been given reprieve of the frogs, he changed his mind and refused to release the Israelites.
The third plague came without warning:
Lice: When Pharaoh broke his promise, the Lord empowered Moses to cast a new plague. Without warning to Pharaoh, the Lord directed Moses to ask Aaron to wave his rod and strike the ground. When Aaron did so, the dust of the ground turned into lice throughout all Egypt. The lice hit men and all animals.
The Pharaoh's magicians tried to copy the act, but could not do so. They turned to Pharaoh in an attempt to convince him that this was indeed an act of God. Exodus 8:19. But Pharaoh's heart remained hard.
Despite three straight plagues over Egypt, the Pharaoh still would not release the Israelites from slavery. But the Lord was not finished using Moses and Aaron to convince the Pharaoh. Six more plagues would come in two more cycles of three plagues each. A final 10m devastating plague would change the Pharaoh.