God has laws.
Everyone breaks them.
That makes us guilty.
The punishment in this life is misery and death.
The punishment in the afterlife is eternal judgment.
God is a good judge and must punish lawbreakers.
God is merciful and desires to save lawbreakers from the punishment they deserve.
God became a man, Jesus, and lived a perfect life. He never broke God’s law.
Jesus suffered in the place of specific lawbreakers, taking God’s wrath upon himself.
Jesus gave his perfect life, his record of goodness, to those lawbreakers.
This great exchange between Jesus and the lawbreakers made the lawbreakers justified. They are legally “not guilty”.
Jesus’ life and death and resurrection was the work. Justification was the result. We can add nothing to the work Jesus did in order to reduce our guilt or add to our status of goodness. The work of justification is done.
If you are one of the lawbreakers that Jesus did this work for, then you will hear his message. You will believe. You will be grateful. You will change your life in order to obey him because that is your only way of expressing a meager, “Thank you.”