The Lord is the king of this universe. God is love and doesn't want to punish us. Mankind is a sinner.
We will disobey the Lord. So God doesn't want to punish us but he have a sense of justice.
God must punish the sins of mankind. So God solved this problem in the person of Jesus Christ.
Christ is God. He came to this earth. He lived a perfect life and died on the cross. Then he conquered death.
A person can try to do good but the sins remains in the soul. So a person needs to be cleansed by Jesus.
So the person needs to repent from their sins and follow Jesus.