From Corinth, Paul wrote his Second Epistle to the Christians in Thessalonica. Since he had left them, many had backslidden from his own solid and Biblical Postmillennialism.
They had lapsed into screwball Quasi-Zoroastrian Premillennialism. Indeed, they had falsely assumed that Christianity would shrink — and Jesus soon return to rapture His ‘imperilled’ Church, before the Final Judgment.
So Paul now reminded the Thessalonians that Jesus would not return physically until long after the ‘wicked one’ — Antichrist, alias ‘the man of sin’ — had later been revealed. Indeed, only thereafter would Jesus return unto Final Judgment.
The latter could and would occur only after Antichrist had been destroyed by the Church’s Spirit-filled powerful preaching and obeying of God’s Spirit-inspired Word the Holy Bible — when the Gospel had run its "free course" throughout the World. Cf. Second Thessalonians 2:8 to 3:1 with Revelation 13:4 & 15:4 &16:14 & 19:20f.
True, "that wicked one [would indeed] be revealed” or manifested. However, he would be but the entity which “the Lord shall consume with the Spirit of His Mouth” alias the Church’s [Spirit-filled] powerful preaching and obeying of the written Word of God. And because God from the beginning has chosen Christians “unto salvation through sanctification of the Spirit” — “therefore, brothers, keep on standing fast…so that the [Spirit-filled] Word of the Lord may have free course!"
Here, Calvin says: "If prophecy [alias the Spirit-filled forthtelling of God’s Word] is to have its due authority, we must have regard to the Spirit of God!… The Spirit declares that that day [of the Lord] is at hand…in regard to God, with Whom ‘one day is as a thousand years’ (Second Peter 3:8)….
"The false-prophets on the other hand, who are refuted by Paul, were bidding men feel assured of His soon and speedy advent…. [However:] The Day of Christ, he [Paul] says, will not come — until [after] the World has fallen into apostasy, and the rule of Antichrist has held sway in the Church….
"This," explains Calvin, "we see accomplished in Popery…. Anyone who has learned from Scripture what are the things that belong particularly to God, and who on the other hand considers well what the Pope usurps for himself — even though he were a ten-year-old boy, will not have much difficulty in recognizing Antichrist….
"The reign of Antichrist will be temporary…. He [the Spirit-filled Paul] had predicted the destruction of the reign of Antichrist, and now describes the manner of his destruction. He will be annihilated by the Word of the Lord….
"Paul does not think that [the Spirit-filled] Christ will accomplish this in a single moment…. [The Spirit-filled] Christ will scatter the darkness in which Antichrist will reign — by the rays which He will emit before His coming….
"This [Spirit-filled] victory of the Word will therefore be seen in the World. For [the Spirit] or ‘the Breath of His Mouth’ means simply His Word, as in Isaiah 11:4…. True and sound doctrine…is represented as being sufficient to put an end to all ungodliness, and…destined…to be victorious over all the devices of Satan…. The [Spirit-filled] preaching of this doctrine, is referred to as [the Spirit-anointed] Christ’s ‘coming’ to us….
"The Kingdom of Christ consists of the doctrine of truth and the power of the Spirit…. [The Spirit-anointed] Christ, by the doctrine of His Gospel, enlightens our minds to eternal life…. Christ puts forth the power of His Spirit for our salvation….
"The adversary, by the efficacy of Satan, alienates us from the Holy Spirit and conforms…creatures in their error by his delusions…. God enlightens us inwardly by His Spirit, so that His doctrine may take effect in us….