“Your iniquities have separated you from your God” (Isaiah 59:2).
Sin is a kind of ‘red card’, like in a soccer match. It means: “You are out!” Religion demands from its followers a rigid effort to act correctly and, once a sin is committed, to try to compensate for it somehow with ‘good deeds’. That makes us feel good. “I can! I am able!” It is part of our nature to try to pacify God by compensating for our sin. Ultimately that amounts to the assumption that as long as I do not commit shirk or kufr, I do not really need God. This is equal to a convicted criminal expecting to be released on his promise of doing a ‘good deed’ to compensate for his crime and, in addition, not to repeat that crime. God’s righteousness does not work like that neither does it reflect His mercy and grace. Unless God removes it, sin separates an offender from Him for all eternity!
The last book in the Bible records a vision of the devastating consequence of that:
“I saw the dead, great and small, standing before the throne, and books were opened . . . The dead were judged according to what they had done according to the books” (Revelation 20:12).
Judgement Day is harvest day. Everybody receives what he or she has planted, that is what he deserves. It is the execution of God’s judgement.
The Judge will be Jesus, as He Himself stated:
“When the Son of man (i.e. Jesus) comes in His glory, and all the holy angels with Him, He will sit on His throne in heavenly glory. All the nations will be gathered before Him, and He will separate the people one from another as a shepherd separates the sheep from the goats. He will put the sheep on His right and the goats on His left . . . Then the King will say to those on His right, ‘Come, you who are blessed by my Father; take your inheritance, the kingdom prepared for you since the creation of the world’ . . . Then He will say to those on His left, ‘Depart from me, you who are cursed, into the eternal fire prepared for the devil and his angels’, then they will go away to eternal punishment, but the righteous to eternal life” (Matthew 25:31 – 34, 41, 46).