Often people see themselves as bad. And they are bad. They did follow Satan. They were God's enemies.
But God sent Jesus.
God's family celebrate Jesus' coming. They celebrate Jesus' death and the right standing with God that it brought us. It is right for us to celebrate this. It is right to celebrate God's mercy. It is right to celebrate God's love. It is right to celebrate God's justice being satisfied at the cross.
But Jesus did more than just die. He rose.
Scripture says that when Jesus died, we died with him. We were buried with him. And we rose with him.
Obviously, we don't have nail holes in our hands. We weren't wrapped in burial clothes. We weren't laid in a tomb. And on the third day, we didn't help roll away the stone. But there are some places in Scripture where the writer seems to be saying that we were. Metaphorical? Metaphysical?
Is the writer trying to point out that there is a reality beyond a judicial pronouncement?
It is one thing to be arrested, go to trial, be pronounced guilty ... but your sentence has already been served, and not by you. It is another to be merged with another person, and to receive all the good he receives.
This judicial pronouncement that our punishment has been, not forgotten, no excused, but satisfied explains why we are free, citizens of God's kingdom, and members of God's family. But it does not explain changes in attitudes, values, goals, practices and pursuits. It doesn't explain changes in motivation.
It is almost like there has been a DNA transplant. Now, as the cell with the new DNA begins to multiply, a new person is being creted, step by step, cell by cell.