So Moses met up with Aaron and they went back to Egypt to talk to the elders of Israel. Moses did a couple of magic tricks and that was good enough for the elders. They agreed to let Moses go to Pharaoh to see if he would set them free.
Before we go any further it’s important to note that Moses and the current Pharaoh had to have had a history together. After all, this Pharaoh was the heir to the Pharaoh whose daughter was Moses’ adopted mother, so there’s a good chance he’s Moses’ uncle. It’s been surmised that they could be cousins or even half-brothers depending on who married whom within the family. Incest was common back then, especially within royal families. Nothing is ever mentioned about this but it’s pretty certain these two guys knew each other and, from the events that follow, it’s apparent they didn’t like each other.
So Moses went up to Pharaoh and said the Israelites just wanted to go out into the desert for a few days to sacrifice and celebrate their God. But Pharaoh knew it was a scam from the get-go. He knew they were going to make a run for it and he wasn’t about to let that happen. He needed his slaves and he needed them to behave. So just to show his authority, he decided to make the Israelite slaves’ lives even more miserable.
I’m not sure what Moses expected but he seems to have made things even worse than before. The people groaned, Moses was disheartened and the elders were seriously pissed. But God had a plan. In fact God let on that he’d hardened Pharaoh’s heart on purpose just so he could beat his ass later and show off his awesome power.