Jamieson, Fausset and Brown on 1 Timothy 1:20

20. Hymenaeus--There is no difficulty in supposing him to be the Hymenæus of 2Ti 2:17. Though "delivered over to Satan" (the lord of all outside the Church, Ac 26:18, and the executor of wrath, when judicially allowed by God, on the disobedient, 1Co 5:5; 2Co 12:7), he probably was restored to the Church subsequently, and again troubled it. Paul, as an apostle, though distant at Rome pronounced the sentence to be executed at Ephesus, involving, probably, the excommunication of the offenders (Mt 18:17, 18). The sentence operated not only spiritually, but also physically, sickness, or some such visitation of God, falling on the person excommunicated, in order to bring him to repentance and salvation. Alexander here is probably "the coppersmith" who did Paul "much evil" when the latter visited Ephesus. The "delivering him to Satan" was probably the consequence of his withstanding the apostle (2Ti 4:14, 15); as the same sentence on Hymenæus was the consequence of "saying that the resurrection is past already" (2Ti 2:18; his putting away good conscience, naturally producing shipwreck concerning FAITH, 1Ti 1:19. If one's religion better not his morals, his moral deficiencies will corrupt his religion. The rain which falls pure from heaven will not continue pure if it be received in an unclean vessel [Archbishop Whately]). It is possible that he is the Alexander, then a Jew, put forward by the Jews, doubtless against Paul, at the riot in Ephesus (Ac 19:33).

that they may--not "might"; implying that the effect still continues--the sentence is as yet unremoved.

learn--Greek, "be disciplined," namely, by chastisement and suffering.

blaspheme--the name of God and Christ, by doings and teachings unworthy of their Christian profession (Ro 2:23, 24; Jas 2:7). Though the apostles had the power of excommunication, accompanied with bodily inflictions, miraculously sent (2Co 10:8), it does not follow that fallible ministers now have any power, save that of excluding from church fellowship notorious bad livers.