One rule in reading the bible is to always interpretation the Old Testament in light of the New Testament. The Old Testament is written from the perspective that God was behind everything that happened. Job thought that everything bad that was happening to him was from God. However we see that Satan was an instigator. In Exodus we read some verses that claim God hardened Pharoah's heart (Exodus 7:3, 10:1) but we cannot ignore the other verses that clearly show that Pharaoh had a part to play in this because it also says that Pharaoh was stubborn (7:14) and he hardened his own heart (8:15&32). In the New Testament we see Jesus dealing with the Devil in a whole different light than what we see in the OT. We see Jesus being tempted by the Devil, as well as Jesus casting some demons out of people. People who have never been exposed to this part of the gospel sometimes have a fatalistic view of God regarding all the evil in the world. If they do not understand that the Devil is the destroyer and one to resist they simply throw up their hands and don't know what to do or even how to pray, and simply say "well God's in control", or "its all God". Apostle Peter wrote that we should resist the adversary who prowls about like a roaring lion (1 Pet.5:8-9). It is rather difficult to resist him if one thinks God is doing everything. When Muslim terrorists storm a church and murder children in cold blood we have to recognize that evil exists and must be confronted.
Apostle Paul's second letter to the Thessalonians he writes, "the one whose coming is in accord with the activity Satan, with all power and signs and false wonders, and with all the deception of wickedness for those who perish, because they did not receive the love of the truth, so as to be saved. And for this reason God will send upon them a deluding influence so that they might believe what is false." (2 Thess. 2:9-12)
So what happened to Pharaoh was not only God's vindication for the sake of the children of Israel but it was judgment upon the willfully stubborn heart of Pharaoh who followed the deceptive works of the magicians (Exodus 7:22). Apostle Paul mentions these two characters, Jannes and Jambres, and warns us that we will be faced with similar seducers in the future. (2 Tim. 3:8-13)
