A falling away. Greek apostasia. A great rebellion or departure from the faith must come before the day of the Lord.

That man of sin... the son of perdition. The same title son of perdition used of Judas (John 17:12). The antichrist figure of the end times is the ultimate fulfillment of the betrayer pattern — claiming to be on God's side while operating against Him.

The defining act of the man of sin — sitteth in the temple of God, shewing himself that he is God. The Antichrist's sin is the original sin of Genesis 3 magnified to the throne — ye shall be as gods.

Daniel 11:36 and Revelation 13 develop the same picture. The final rebellion takes religious form, not secular. The greatest enemy of God positions himself in God's place rather than denying His existence.

The mystery of iniquity doth already work. The spirit that will produce the man of sin is already operative in the world. The seeds of the final apostasy are visible in every age.

He who now letteth will let. Letteth is old English for restrain. Someone or something is currently restraining the full revelation of the man of sin. The identity of the restrainer is debated — the Holy Spirit, civil government, the church's presence. Each interpretation has support.

The Lord shall consume him with the spirit of his mouth. The same imagery as Isaiah 11:4 — with the breath of his lips shall he slay the wicked. Christ destroys the man of sin not by armies but by His mere word.

The brightness of his coming. Greek epiphaneia — the manifestation. The light of His appearing dissolves what darkness had built up.

Received not the love of the truth. A profound diagnosis. It was not that they did not hear truth, did not know it intellectually. They did not love it. Truth was offered; they refused to embrace it.

The gospel asks not just intellectual assent but heart love. The man who can argue the doctrines but does not love them is in the very position 2 Thessalonians 2:10 describes — at risk of receiving strong delusion.

A sobering verse. God Himself sends the delusion. When men refuse the truth, God does not protect them from believing lies. The judicial hardening of Romans 1:24-28 is the same principle.

Implication: the heart that refuses truth is not left to its own confusion. God actively assists the deception by withdrawing protection. The way to be preserved from being deceived is to maintain love of the truth.

After the heavy material on the man of sin, comfort for believers. God hath from the beginning chosen you to salvation. The same God who hardens those who reject truth has chosen His people from before the world.

Through sanctification of the Spirit and belief of the truth. The means by which the elect arrive at salvation. Not bypassing faith and obedience but through them. Election and human responsibility are both true and both necessary.

Stand fast, and hold the traditions which ye have been taught. Apostolic teaching, whether oral (during Paul's visit) or written (his letters), was authoritative. The believer's task is to hold it.

In an age of constant theological reinvention, the command stands. The apostles' doctrine is not raw material to be reshaped; it is treasure to be guarded. Innovation in doctrine is not progress; it is drift toward the man of sin's system.