2Th 2:3 Let no man deceive you by any means: for that day shall not come, except there come a falling away first, and that man of sin be revealed, the son of perdition; Who opposeth and exalteth himself above all that is called God, or that is worshipped; so that he as God sitteth in the temple of God, shewing himself that he is God. Remember ye not, that, when I was yet with you, I told you these things? And now ye know what withholdeth that he might be revealed in his time. For the mystery of iniquity doth already work: only he who now letteth will let, until he be taken out of the way
God dealing with believers’ deceptions and rebellion
8 Then the lawless one will be revealed, whom the Lord will kill with the breath of his mouth, and bring to nothing by the brightness of his coming; even he whose coming is according to the working of Satan with all power and signs and lying wonders, and with all deception of wickedness for those who are being lost, because they didn’t receive the love of the truth, that they might be saved. Because of this, God sends them a working of error, that they should believe a lie; that they all might be judged who didn’t believe the truth, but had pleasure in unrighteousness.
Standing firm in believing the truth
13 But we are bound to always give thanks to God for you, brothers loved by the Lord, because God chose you from the beginning for salvation through sanctification of the Spirit and belief in the truth; to which he called you through our Gospel, for the obtaining of the glory of our Lord Jesus Christ. So then, brothers, stand firm, and hold the traditions which you were taught by us, whether by word, or by letter. Now our Lord Jesus Christ himself, and God our Father, who loved us and gave us eternal comfort and good hope through grace, comfort your hearts and establish you in every good work and word.
Final appeal to stand in grace through faith
16 Now may the Lord of peace himself give you peace at all times in all ways. The Lord be with you all. The greeting of me, Paul, with my own hand, which is the sign in every letter: this is how I write. The grace of our Lord Jesus Christ be with you all. Amen.