Intriguing interpretation of 2 Thessalonians 2:3 by Tyconius (also Ticonius, Tychonius)
For Tyconius, however, the opposite is true. Tyconius understands that the great “falling away” of the end times will not be caused by unfaithful people leaving the Bride of Christ, but rather by the Bride of Christ pulling away from those within her who are unfaithful. In other words, for Tyconius, it is not the infidels who will “fall away” but rather the true believers, who will withdraw from the evil within the Church. A paradoxical reversal indeed.
For Tyconius, it is the new Israel who must depart on her new Exodus. The true Church herself will effect the great apostasy as a way of salvation from her enemies. In a real sense, the true Church will force the apostasy into the light, for the body of the devil, present in the false brothers inhabiting the Church, is already, and always has been, apostate. That fact has merely been concealed.
Expounding on Apocalypse 16:19, which begins, “And the great city was divided into three parts,” Tyconius states: “This great city is all people entirely, everyone who is under heaven, who will be divided into three parts when the church is divided, resulting in the heathen being one part; and the ‘abomination of desolation,’ another; and the church, which will have gone out from the midst of her, a third”. And again, in commenting on Apocalypse 18:4 – And I heard another voice from heaven, saying: Go out from her, my people, so that you do not share in her sins and so that you are not stricken by her plagues – Tyconius writes: “Here he [the Apostle John] shows more fully that Babylon consists of two separate parts, external and internal, out of which also holy people, having been clearly warned by God, will leave.”
Strong's Greek: 646. ἀποστασία (apostasia) -- defection, revolt
Ratzinger, Tyconius, and Fatima: An Interpretive Key for the End Times.
CATHOLIC ENCYCLOPEDIA: Ticonius (379-423)