Moses does no such thing!! There are 20 accounts covering the hardening of Pharaohs heart, ten Gods doing an 10 Pharaoh did himself, consequently, Mose had nothing to do with the actual release.
“And I have said, I will bring you up out of the affliction of Egypt unto the land of the Canaanites, and the Hittites, and the Amorites, and the Perizzites, and the Hivites, and the Jebusites, unto a land flowing with milk and honey. And they shall hearken to thy voice: and thou shalt come, thou and the elders of Israel, unto the king of Egypt, and ye shall say unto him, The Lord God of the Hebrews hath met with us: and now let us go, we beseech thee, three days' journey into the wilderness, that we may sacrifice to the Lord our God. And I am sure that the king of Egypt will not let you go, no, not by a mighty hand. And I will stretch out my hand, and smite Egypt with all my wonders which I will do in the midst thereof: and after that he will let you go. And I will give this people favour in the sight of the Egyptians: and it shall come to pass, that, when ye go, ye shall not go empty.” Exodus 3:17-21
“And I will harden Pharaoh's heart, and multiply my signs and my wonders in the land of Egypt. But Pharaoh shall not hearken unto you, that I may lay my hand upon Egypt, and bring forth mine armies, and my people the children of Israel, out of the land of Egypt by great judgments.” Exodus 7:3-4
“And the Lord said unto Moses, Pharaoh shall not hearken unto you; that my wonders may be multiplied in the land of Egypt. And Moses and Aaron did all these wonders before Pharaoh: and the Lordhardened Pharaoh's heart, so that he would not let the children of Israel go out of his land.” Exodus 11:9–10
It seems unjust for God to harden Pharaoh’s heart and then to punish Pharaoh and Egypt for what Pharaoh decided when his heart was hardened. Why would God harden Pharaoh’s heart just so He could judge Egypt more severely with additional plagues?
First, Pharaoh was not an innocent or godly man. He was a brutal dictator overseeing the terrible abuse and oppression of the Israelites, who likely numbered over 2.0 million people at that time. The Egyptian pharaohs had enslaved the Israelites for 400 years. A previous pharaoh—ordered that male Israelite babies be killed at birth.
“And the king of Egypt spake to the Hebrew midwives, of which the name of the one was Shiphrah, and the name of the other Puah: And he said, When ye do the office of a midwife to the Hebrew women, and see them upon the stools; if it be a son, then ye shall kill him: but if it be a daughter, then she shall live.” Exodus 1:15-16
The pharaoh (Tutmose II) God hardened was an evil man, and the nation he ruled agreed with, or at least did not oppose, his evil actions.
Second, on least a couple occasions, Pharaoh hardened his own heart against letting the Israelites go: “But when Pharaoh saw that there was respite, he hardened his heart, and hearkened not unto them; as the Lord had said.” Exodus 8:15
“And Pharaoh hardened his heart at this time also, neither would he let the people go.”Exodus 8:32
God and Pharaoh were both active in one way or another in the hardening of Pharaoh’s heart. As the plagues continued, God gave Pharaoh increasingly severe warnings of the final judgment to come. Pharaoh chose to bring further judgment on himself and his nation by hardening his own heart against God’s commands.
As a result of Pharaoh’s hard-heartedness, God hardened Pharaoh’s heart even further, allowing for the last few plagues and bringing God’s full glory into view (Exodus 9:12; 10:20, 27). Pharaoh and Egypt had brought these judgments on themselves with 400 years of slavery and mass murder. Since the wages of sin is death (Romans 6:23), and Pharaoh and Egypt had horribly sinned against God, it would have been just if God had completely annihilated Egypt. Therefore, God’s hardening Pharaoh’s heart was not unjust, and His bringing additional plagues against Egypt was not unjust. The plagues, as terrible as they were, actually demonstrate God’s mercy in not completely destroying Egypt, which would have been a perfectly just penalty.
“For the scripture saith unto Pharaoh, Even for this same purpose have I raised thee up, that I might shew my power in thee, and that my name might be declared throughout all the earth. Therefore hath he mercy on whom he will have mercy, and whom he will he hardeneth.” Romans 9:17-18