New Defender's Study Bible Notes
1:20 Hymenaeus. The blasphemy of Hymenaeus, and presumably that of Alexander, was denial of the future bodily resurrection (II Timothy 2:17-18), evidently holding that the resurrection was simply the spiritual change when a person is born again. This was called blasphemy, because it denied not only the teachings of Paul (e.g., I Thessalonians 4:16-17), but also of Christ Himself (e.g., John 5:25-29).
1:20 delivered unto Satan. The action of “[delivering] unto Satan” probably includes more than excommunication from the church. The same action mentioned in I Corinthians 5:5 speaks of “destruction of the flesh” as a possible chastisement, not carried out by the church, but by the Lord.