Sam Dawson "It's evident that Hymenaeus and Philetus believed in the resurrection as the hope of Israel as the gospel which Paul preached, but they were mistaken on the time element of it." gospelthemes.com/eschatologyfaq.htm
William Bell "Briefly stated, if we do in fact have a resurrection already past, it means one has erred and destroys the faith of others. It is, on the surface a seeming just charge. However, the failure to address the time issues of a passage in which timing is a critical component is a far too hasty assessment. Paul draws attention to their words, "resurrection already past. That is a time issue. It implies that it must be compared or contrast with something that can be measured as "not already." "Now that we have our TEMPORAL MEASURING LINE, the A.D. 70 destruction of Jerusalem as the imminent event and time of the Lord's return, we can clearly see the fallacy of the Hymenaen heresy in saying that the resurrection had occurred. It was an error in time to teach that the event happened too soon."
Don Preston "They were not affirming the past occurrence of the end of the physical cosmos. They were affirming — prematurely — the full revelation of salvation."