For that day will not come, unless the rebellion comes first, and the man of lawlessness is revealed, the son of destruction, who opposes and exalts himself against every so-called god or object of worship, so that he takes his seat in the temple of God, proclaiming himself to be God. - 2 Thessalonians 2:3-4
Until then
He who now restrains the lawless one will do so until he is to be revealed in his time. The mystery of lawlessness is already at work, though. (2 Thessalonians 2:6-7)
False coming
The coming of the Jesus will be proceeded by the coming of the lawless one. His coming is by the activity of Satan with all power and false signs and wonders, and with all wicked deception for those who are perishing, because they refused to love the truth and so be saved. God will send them a strong delusion, so they may believe what is false and may be condemned for not believing the truth but having pleasure in unrighteousness. (2 Thessalonians 2:9-12)
When is the day of the Lord?
For you yourselves are fully aware that the day of the Lord will come like a thief in the night. - 1 Thessalonians 5:2
People will feel there is peace and security when sudden destruction comes upon them without escape. (1 Thessalonians 5:3)
But we are not in darkness! Keep awake and be sober. Put on the breastplate of faith and love and the helmet of the hope of salvation. Encourage each other and build each other up, since God has destined us not for wrath but to obtain salvation through our Lord Jesus Christ. (1 Thessalonians 5:4-11)
The day of the Lord will not come unless the rebellion comes first and the man of lawlessness is revealed. If the man of lawlessness will literally take his literal seat in the literal temple of God, that also necessitates the rebuilding of the temple. (2 Thessalonians 2:1-3)
What will happen that day?
The Lord Jesus will kill the man of lawlessness with the breath of his mouth and bring to nothing by the appearance of his coming. (2 Thessalonians 2:8)
The house of Jacob shall be a fire, and the house of Joseph a flame, and the house of Esau stubble; they shall burn them and consume them, and there shall be no survivor for the house of Esau, for the LORD has spoken. (Obadiah 18)