Most Christians believe the Great White Throne Judgment is when the non-Christian worldly sinners are pronounced unfit for the Kingdom of God and are then cast alive into the lake of fire to be tormented for the rest of eternity. In Matthew 7:20-23 Jesus is not talking about the sinners of the world, he is talking about those who proclaim to be his followers. He is warning his followers to be careful what they believe and who they follow, because it will make a difference to them in the end.
22 On the last day many people will say to me, ‘You are our Lord! We spoke for you. And through you we forced out demons and did many miracles.’ 23 Then I will tell them clearly, ‘Get away from me, you who do evil. I never knew you.’
Many people may cast out demons, preach the name of Jesus to the masses and do miracles, but if they follow the wrong teachers and beliefs they will be rejected and thrown into the fire. Even the elect need to be careful they are not tricked by wolves who pray on them. The only way to know you are on the right path is to strictly follow what the Bible teaches. Do you follow what others say or do you prove your beliefs by looking at all relevant scripture? What was the lie Satan told Eve?
Matthew 24:24 English Standard Version
24 For false christs and false prophets will arise and perform great signs and wonders, so as to lead astray, if possible, even the elect.
2 Peter 2:1 Easy-to-Read Version
2 In the past there were false prophets among God’s people. It is the same now. You will have some false teachers in your group. They will teach things that are wrong—ideas that will cause people to be lost. And they will teach in a way that will be hard for you to see that they are wrong. They will even refuse to follow the Master who bought their freedom. And so they will quickly destroy themselves.
Ephesians 4:14 International Standard Version
14 Then we will no longer be little children, tossed like waves and blown about by every wind of doctrine, by people’s trickery, or by clever strategies that would lead us astray.
2 Timothy 4:4 Living Bible
4 They won’t listen to what the Bible says but will blithely follow their own misguided ideas.
2 Corinthians 11:3 Modern English Version
3 But I fear that somehow, as the serpent deceived Eve through his trickery, so your minds might be led astray from the simplicity that is in Christ.