2 Timothy 2:18

“Who concerning the truth have erred, etc.] That is, the two persons just mentioned; they fell from the truth, wandered and departed from it; they did not keep to the Scriptures of truth, but deviated from them; they missed that mark, and went astray into gross errors and mistakes; rejected the Gospel, the word of truth, in general, and particularly in saying, that the resurrection is past already; and no other is to be expected; or that there was no future resurrection of the dead: their error was, as some think, that there is no other resurrection than that of parents in their children, who, though they die, live in their posterity; or than the resurrection of Christ, and of the saints,…”

“erred--Greek, "missed the aim" (see Ti1 6:21). is past already--has already taken place. The beginnings of the subsequent Gnostic heresy already existed. They "wrested" (Pe2 3:16) Paul's own words (Rom 6:4; Eph 2:6; Col 2:12) "to their own destruction," as though the resurrection was merely the spiritual raising of souls from the death of sin. Compare Co1 15:12, where he shows all our hopes of future glory rest on the literal reality of the resurrection. To believe it past (as the Seleucians or Hermians did, according to AUGUSTINE [Epistles, 119.55, To Januarius, 4]), is to deny it in its true sense. overthrow--trying to subvert "the foundation" on which alone faith can rest secure (Ti2…”

“Who concerning the truth have erred - To what extent they had erred is unknown. Paul mentions only one point - that pertaining to the resurrection; but says that this was like a gangrene. It would certainly, unless checked, destroy all the other doctrines of religion. No man can safely hold a single error, any more than he can safely have one part of his body in a state of mortification. Saying that the resurrection is past already - It is not known in what form they held this opinion. It may have been, as Augustine supposes, that they taught that there was no resurrection but that which occurs in the soul when it is recovered from the death of sin, and made to live anew. Or it may be that…”

“Saying the resurrection is already past - Perhaps asserting that it is only the spiritual passing from death unto life. 2 Timothy 2:19”

“2:18 claiming that the resurrection of the dead has already occurred: Cp. 2 Thes 2:2. These false teachers might have twisted Paul’s own teaching on the resurrection of the dead (Rom 6:5; Gal 2:20; Eph 1:3; 2:6; 5:14; Col 2:12; 3:1-4) by teaching that they already fully participated in the heavenly life, and perhaps that physical resurrection would not occur. They could have concluded from this that one’s conduct in the body (i.e., morality) was irrelevant, since their mortal bodies could have no impact on their eternal spirits. Or, they could have gone the other way, toward world-denying asceticism (1 Tim 4:3; see Col 2:8, 16-23), with the idea that enjoyment of material things is…”

“concerning: Mat 22:29; Ti1 1:19, Ti1 6:10, Ti1 6:21; Heb 3:10; Jam 5:19 that: Co1 15:12; Col 3:1 overthrow: Ti2 2:14; Mat 15:13; Luk 8:13, Luk 22:31, Luk 22:32; Act 5:39; Co1 11:19; Jo1 2:19 2 Timothy 2:19”