They perish because they refused to love the truth and so be saved.
2 Thessalonians 2:10b

For this reason God sends them a powerful delusion

so that they will believe the lie and so that all will be condemned who have not believed the truth but have delighted in wickedness.
2 Thessalonians 2: 11, 12

” Their sin is this: They believed not the truth, but had pleasure in unrighteousness: they did not love the truth, and therefore they did not believe it;

and, because they did not believe the truth, therefore they had pleasure in unrighteousness, or in wicked actions, and were pleased with false notions.

Note, An erroneous mind and vicious life often go together and help forward one another.

Their ruin is thus expressed: God shall send them strong delusions, to believe a lie.

Thus he will punish men for their unbelief, and for their dislike of the truth and love to sin and wickedness; not that God is the author of sin, but in righteousness he sometimes withdraws his grace from such sinners as are here mentioned; he gives them over to Satan, or leaves them to be deluded by his instruments;

he gives them up to their own hearts’ lusts, and leaves them to themselves, and then sin will follow of course, yea, the worst of wickedness, that shall end at last in eternal damnation. God is just when he inflicts spiritual judgments here, and eternal punishments hereafter, upon those who have no love to the truths of the gospel,

who will not believe them, nor live suitably to them, but indulge false doctrines in their minds, and wicked practices in their lives and conversation.”

from Matthew Henry’s Commentary on 2 Thessalonians 2:11,12

 

But we ought always to thank God for you, brothers loved by the Lord, because from the beginning God chose you to be saved through the sanctifying work of the Spirit and through belief in the truth.
2 Thessalonians 2:13

” When we hear of the apostasy of many, it is a great comfort and joy, that there is a remnant according to the election of grace, which does and shall persevere; especially we should rejoice, if we have reason to hope that we are of that number. The preservation of the saints, is because God loved them with an everlasting love, from the beginning of the world.”

from Matthew Henry’s Commentary on  2 Thessalonians  2:13

 

This  blog was originally posted on November 23, 2020. It bares repeating.