One of the complaints about penal substitutionary atonement is how it makes the ministry of Jesus soteriologically irrelevant. Jesus was "born to die," so his life and ministry was just a prelude to the real action: dying on the cross for our sins. There is little connection in this view between Jesus' ministry and what he does on the cross.
But as I point out in Reviving Old Scratch, Christus Victor atonement sees the life and ministry of Jesus as an important and critical part of salvation. Again, in Christus Victor atonement Jesus sets us free from the power of the devil. And while this emancipation reaches its climax on the cross (Col. 2.15), freeing people from the power of the devil characterized the whole of Jesus' ministry. Jesus' confrontation with Satan is the narrative glue that holds the gospels together.
Here's how Jesus described what he was doing:
Then they brought him a demon-possessed man who was blind and mute, and Jesus healed him, so that he could both talk and see.
All the people were astonished and said, "Could this be the Son of David?"
But when the Pharisees heard this, they said, "It is only by Beelzebul, the prince of demons, that this fellow drives out demons."
Jesus knew their thoughts and said to them, "Every kingdom divided against itself will be ruined, and every city or household divided against itself will not stand. If Satan drives out Satan, he is divided against himself. How then can his kingdom stand? And if I drive out demons by Beelzebul, by whom do your people drive them out? So then, they will be your judges. But if it is by the Spirit of God that I drive out demons, then the kingdom of God has come upon you. Or again, how can anyone enter a strong man's house and carry off his possessions unless he first ties up the strong man? Then he can plunder his house."
Jesus describes his ministry as robbery.
For the legally minded, burglary is "breaking in" and stealing, but there is no victim involved. What Jesus describes is worse, it's not burglary but robbery, using force to steal from a person. Jesus breaks into the house of a "strong man," ties him up, and then robs him, carrying off his possessions. This is Christus Victor salvation.
People are held in bondage to Satan--human beings are "possessions" in the devil's house--and Jesus breaks in to tie him up and set his hostages free. This emancipation didn't wait for the cross but began at the very start of Jesus' ministry. As Peter concisely summarized in Acts 10:
God anointed Jesus of Nazareth with the Holy Spirit and power, and he went around doing good and healing all who were under the power of the devil.