This is Paul writing to the followers of Jesus in Thessalonica.
He's explaining some end times stuff.
I know it's kind of confusing, but just absorb it...
especially the parts I underlined at the end.
Just remember for future reference the things Paul writes here...
2 Thessalonians 2
1 Now, dear brothers and sisters, let us clarify some things about the coming of our Lord Jesus Christ
and how we will be gathered to meet him.
2 Don't be so easily shaken or alarmed by those who say that the day of the Lord has already begun.
Don't believe them,
even if they claim to have had a spiritual vision,
3 Don't be fooled by what they say.
For that day will not come until there is a great rebellion against God and the man of lawlessness is revealed—the one who brings destruction.
4 He will exalt himself and defy everything that people call god and every object of worship.
He will even sit in the temple of God, claiming that he himself is God.
5 Don't you remember that I told you about all this when I was with you?
6 And you know what is holding him back,
for he can be revealed only when his time comes.
7 For this lawlessness is already at work secretly,
and it will remain secret until the one who is holding it back steps out of the way.
8 Then the man of lawlessness will be revealed,
but the Lord Jesus will kill him with the breath of his mouth and destroy him by the splendor of his coming.
9 This man will come to do the work of Satan with counterfeit power and signs and miracles.
10 He will use every kind of evil deception to fool those on their way to destruction,
because they refuse to love and accept the truth that would save them.
11 So God will cause them to be greatly deceived,
and they will believe these lies.
12 Then they will be condemned for enjoying evil rather than believing the truth.