Summary: Thew opposition is great and the temptation to compromise is also great. but God encourages them to hold firm.
As we move on from Ephesus and Smyrna to Pergamum and Thyatira we see the intensity of opposition and persecution increasing. While in Smyrna there was a warning of possible death for Christ, in Pergamum we find it’s happened. Here maintaining belief in Christ has cost Antipas his life.
Yet even the reality of that sort of opposition hasn’t stopped them holding fast to the name of Christ. He knows their context: "where Satan’s throne is". Like the other 2 cities, Pergamum was a large city with a well established pagan system of worship. The greatest of these altars was that of Zeus, decorated with sculptures of serpents - which may be the reference to Satan’s throne, though there were plenty of other possibilities.
In any case their situation was such that they needed to remain vigilant if they were to hold fast to the truth. And so Jesus comes to them as the one with the two edged sword. Now remember, in ch 1 this is the sword of God’s word, coming from his mouth. So the issue here may be their attitude to God’s word - can you trust it or does it need reinterpretation or nuancing?
Similarly in Thyatira they live in a pagan city. Here the great temple is that of Apollo, the sun God. Apollo is the son of Zeus. So how does Jesus present himself? As the Son of God; as one whose eyes are like blazing fire. Jesus’ presence is such as to overwhelm that of Apollo or any false god. And they’re praised because their last works are greater than their first. They’re growing in their faith; they’re getting better at it. Unlike Ephesus where they’d lost their first love, this church is growing in love.
But in both cities there was a problem. They’d allowed people to come in who were leading Christians astray.
Each of these is given a nickname. These aren’t their real names. Rather they’re names that are meant to characterise the errors they’re leading people into.
First, in Pergamum, there’s Balaam. Balaam was the prophet, during the Exodus, who was paid to put a curse on the people of Israel as they neared the promised land, though in the end God prevented him from doing it. He’s also the one who was blamed for sending the Moabite women to seduce the Israelite men into taking part in sacrificial orgies devoted to Baal, as a result of which 24,000 people died under God’s judgement.
So what was it that this modern day Balaam was doing in Pergamum? Well, it seems he was preaching a message of accommodation, of adopting some of the practices of the culture in order to live and maybe even prosper in that culture.
The phrase "food sacrificed to idols" gives us a clue. In the context, most tradespeople would have had to belong to a guild if they wanted to practice their trade. And part of belonging to a guild was taking part in their ritual meetings, where the food being served would have been offered to their patron deity. So there’s an economic issue here for a Christian who wants to remain faithful to God. How do you practice your trade if you can’t be part of the guild that controls the trade? Your whole livelihood is affected.