Was Paul's opposition only from Jews, or was there more behind it?
Paul's opposition was not solely from Jews. While his chief opposition came from Jews—both believing Jews and those still steeped in Judaism—there was also a satanic power from every direction, because Satan did not want the gospel going to the Gentile world.
Les explains that Paul's suffering in 2 Timothy 1:12 had more than one source. The chief opposition was the Jew, including believing Jews and those still steeped in Judaism, but it was not the Jew alone. A satanic power opposed him from every direction. Satan did not want the gospel going to the Gentile world. Les notes that Satan hated the gospel going to Israel throughout the Old Testament, but the gospel to the masses of Gentiles was the last thing he wanted. Paul therefore suffered for these things, yet he was not ashamed, because he knew whom he had believed. Despite difficulties, sickness, sorrow, and suffering, he never doubted the God he served.
For the which cause I also suffer these things: nevertheless I am not ashamed: for I know whom I have believed, and am persuaded that he is able to keep that which I have committed unto him against that day.