What does 2 Timothy 2:18 mean?

Hymenaeus and Philetus are mentioned as part of a group from Ephesus who had deviated from the "sound teachings" Paul mentioned earlier (2 Timothy 1:13; 1 Timothy 6:21). One specific error coming from these men was their claim "that the resurrection has already happened." Paul addressed a similar problem to the Thessalonian Christians, teaching, "For this we declare to you by a word from the Lord, that we who are alive, who are left until the coming of the Lord, will not precede those who have fallen asleep" (1 Thessalonians 4:15). He had to remind them that the resurrection had not taken place yet. When it does take place, the dead in Christ will rise first followed by all living believers (1 Thessalonians 4:17). This was to be an encouragement to believers, not a source of controversy (1 Thessalonians 4:18).

This false teaching about the resurrection was causing a crisis of faith for some of the less-savvy Christians in Ephesus. Not every Christian in Ephesus was fooled by this false teaching, but some were. It had become a large enough problem for Paul to address in both 1 and 2 Timothy, and is still on his mind while in prison and expecting to soon die. He stood firmly against false teaching, even in his last days, and instructed Timothy to do the same.