Hymenaeus was an early Christian from Ephesus

Ephesus

Ephesus was an ancient Greek city, and later a major Roman city, on the west coast of Asia Minor, near present-day Selçuk, Izmir Province, Turkey. It was one of the twelve cities of the Ionian League during the Classical Greek era...

, an opponent of the apostle Paul, who associates him with Alexander

Alexander (Ephesian)

Alexander was an early Christian, one of two heretical teachers at Ephesus—the other being Hymenaeus—against whom Paul warns Timothy. Hymeneus and Alexander were proponents of antinomianism, the belief that Christian morality was not required...

 and Philetus

Philetus (Ephesian)

Philetus was an early Christian mentioned by Paul, who warns Timothy against him as well as against his associate in error, Hymenaeus. The apostle speaks of Hymeneus and Philetus as instances of men who were doing most serious injury to the church by their teaching, and by what that teaching...

.

In 1 Timothy 1:20, Hymenaeus is included in the "some" who had put away faith and a good conscience and who had made shipwreck concerning faith. The apostle adds that he had delivered Hymenaeus and Alexander to Satan, that they might learn not to blaspheme. Some have viewed this statement as similar to 1 Corinthians 5:5, where Paul commands the church to expel a member engaging in sexual immorality, in the hopes that his spirit would eventually be saved as a result of this discipline.

Hymenaeus and Philetus are included among persons whose profane and vain babblings will increase towards more ungodliness, and whose teaching "will spread as a cancer." (2 Tim 2:17, NLT). The apostle declares that Hymenaeus and Philetus are examples of those just described, and he adds that those two persons "concerning the truth have erred, saying that the resurrection is past already, and overthrow the faith of some." Then, for the guidance of Timothy, he goes on to say the seal upon the foundation of God is, "The LORD knows those who are his,” and “All who belong to the LORD must turn away from evil." (2 Tim 2:19, NLT)

The inference intended is, that though Hymenaeus and Philetus had professed their faith in Christ, they did not turn away from evil. There is no doubt in regard to the identity of this Hymenaeus with the person of the same name in 1 Tim. Accordingly, the facts mentioned in the two epistles must be placed in the following order: That though Hymenaeus had, 1) made a public and Christian profession of faith in Christ, yet he had, 2) not turned away from evil, but by his profane teaching (see below), 3) went towards more ungodliness. This led to, 4) his abandoning his faith and a good conscience, thus he brought about, 5) the end result of his faith being shipwrecked.

The error, therefore, of Hymenaeus and his two companions would amount to this: They taught that "the resurrection

Resurrection of the dead

Resurrection of the Dead is a belief found in a number of eschatologies, most commonly in Christian, Islamic, Jewish and Zoroastrian. In general, the phrase refers to a specific event in the future; multiple prophesies in the histories of these religions assert that the dead will be brought back to...

 is past already,", circa 50AD–65AD, and that there would be no future resurrection.

Hymenaeus and Philetus may have believed in a nascent form of the Christian heresy

Heresy

Heresy is a controversial or novel change to a system of beliefs, especially a religion, that conflicts with established dogma. It is distinct from apostasy, which is the formal denunciation of one's religion, principles or cause, and blasphemy, which is irreverence toward religion...

 of Gnosticism

Gnosticism

Gnosticism is a scholarly term for a set of religious beliefs and spiritual practices common to early Christianity, Hellenistic Judaism, Greco-Roman mystery religions, Zoroastrianism , and Neoplatonism.A common characteristic of some of these groups was the teaching that the realisation of Gnosis...

.