Simon, the temple captain who argued with the high priest, Onias, whether the funds should be used for the poor or for the king (3:1-12), continued the disagreement by slandering him by saying he was the one who was the cause of the attempted raid of the temple by Heliodot (who after a prayer by Onias had converted).
Simon did not give up. He claimed Onias was the one who had instigated the raid on the temple funds. One his agents committed murders; Apolonius, the govenor of Coelesyria and Phoenicia, joined his cause. In response, Onias appealed to the king to bring peace.
But the temple was not safe yet. Jason, the brother of Onias, had attained the role of high priest by offering a bribe to the king and promising to build a gymnasium and recruit younth to be part of it. A gym sounds good to us now. Young people exercising sounds good now. But, we're reading about then not now. Then what was happening was that the young were being converted from Judaism into Hellenism; that is, from religion to something that was not.
When the gymnasium was established, the priests neglected their religious duties in order to spend more time wrestling and discus-throwing. Quadrennial games were held at Tyre attended by the king. Money intended for the temple was used to build ships.
When I was a teenager, our MYF (we weren't united, yet) danced but the Baptist youth group certainly did not. What are some current differences of opinion about what is proper at church and what is not?