LEFT BEHIND: One of the primary reasons Paul wrote this second letter to the Thessalonians is that they had gotten the idea that somehow the Day of the Lord (flashback) had come and gone and somehow they never got invited to the party (v2). Paul wants to reassure them that this isn't the case at all. Paul uses blurry language to describe what must happen before the Day of the Lord comes, but having just finished reading Revelation (which would not be written until several decades after Paul's letters to Thessalonica), we know that the Day of the Lord will not be an event anybody will somehow miss.
MY, WHAT FRESH BREATH YOU HAVE: The mysterious man of lawlessness (MoL) is being restrained now, but a time is coming when the restraint will be removed (v7) and he will inject himself into every aspect of society (v4). But although the MoL will draw as much attention to himself as possible, is doom will be quick and total, and in a somewhat anticlimactic finish, will be crushed by the breath of the Lord Jesus (v8). But perhaps you remember that the word 'breath' in the Bible means more than just exhaled air, it also means Spirit. Not only was the terrible swift sword coming out of Christ's mouth in Revelation 19 a picture of His 'breath,' but remember that the words you read each day in the Bible are God-breathed. You are experiencing the same power, albeit in a much different way, that the MoL will experience on the Day of the Lord.
IF YOU DON'T BELIEVE THE TRUTH, YOU'LL FALL FOR ANYTHING: As we see society crumble around us, it's hard to understand why seemingly smart people believe the lies the world puts forward. Today's chapter helps shed some light. Once a person refuses to love the Truth (that is, Jesus) and be saved, God sends them a powerful delusion so that they will believe the lies and will delight in wickedness (v10-12). The process begins with a person's free choice to reject God's Truth, represented in Jesus Christ, and that free choice ends up enslaving that person to lies and wickedness.
IF YOU'RE STILL STANDING, IT'S NOT ON YOUR OWN LEGS: Understanding that so many people have become enslaved to lies might cause you to feel a bit better about yourself because you cling to Truth. You may have a very firm grip on the Truth, but realize you're standing where others have fallen because of the Truth's grip on you. Look at the awesome theology in v13-14:
God chose you
sanctified (made holy)
through believing in the Truth
which He called you to through the gospel
so that you might share in Christ's glory
Follow the AAA Prayer Pattern:
ACKNOWLEDGE WHO GOD IS: God our Father, who loved you and by His grace gave you eternal encouragement and good hope (v16)
ALIGN YOUR LIFE WITH GOD'S WILL: Ask God to continue to encourage your heart and strengthen you in every good deed and word (v16)
ASK GOD FOR WHAT YOU NEED: