Paul was warning the Corinthians that were trying to preach a different gospel.
2 Corinthians 11:13-15 - 13 For such people are false apostles, deceitful workers, masquerading as apostles of Christ. 14 And no wonder, for Satan himself masquerades as an angel of light. 15 It is not surprising, then, if his servants also masquerade as servants of righteousness. Their end will be what their actions deserve.
Paul takes pretty seriously God’s truth. People who are teaching all roads lead to Rome such as Universalism or that there is no Hell are certainly not following the Word of God. Their truth comes from
their own self or understanding.
Satan masquerades around like an angel of light.
Why are people teaching these things? Because there popular for one. They rationale that God can only be love and could never punish anyone for eternity. Is that what the Bible says?
Were His own people punished when they rejected Him? Constantly!
God’s Word when tested is perfect. Man is not. It wasn’t written by men, but by the Spirit of God. To pick and choose which parts of the Bible you want, leads to the above problem of not teaching the truth.
Satan likes it when man gets the courage to be smarter than God. It plays right into his hand.
Their actions in the end according to Paul will lead to what they deserve.
Proverbs 14:12 – 12 There is a way that seems right to a man, but in the end it leads to death.