Jesus summoned the Twelve and began to send them two by two and gave them authority over unclean spirits and to preach repentance. Jesus summoned the Twelve and began to send them two by two and gave them authority over unclean spirits and to preach repentance. In Mathew 9:38, in a setting that leads to the sending of the twelve on their maiden mission, Jesus tells his disciples to ask the Father to send laborers into the vineyard. Jesus’ directive was occasioned by the sheer number of people who were in need of Jesus’ attention. Wherever they had set foot, Jesus and his disciples were met by men and women who were in need of some form of shepherding: the sick, the disillusioned, the poor, the marginalized. The situation was made worse by the blatant display of indifference and disregard on the part of those whose responsibility it was to shepherd the people. And whereas Jesus was more than willing to step in and attend to the needs of these brothers and sisters of his, he must have felt overwhelmed by their vast number. He needed help, and he knew where to get it: the twelve individuals whom he had earlier on designated as apostles.
It was not merely for companionship or out of security concerns that Jesus had recruited the twelve as members of his inner circle. Jesus did not summon the twelve to himself because he was feeling lonely and/or insecure. Rather, Jesus had recruited the twelve so that they could become co-workers with him in the vineyard of the Lord. He needed men and women who were going to share in his mission of proclaiming the good news of the in-breaking of God’s kingdom. And having had the opportunity to watch Jesus up and close as he ministered to the people, the time had now come for the twelve  to take their position at the side of Jesus and assume the task for which they had been “drafted.”
Whereas the mission of the twelve was multifaceted, it is worth noting that in the Gospel according to Mark, driving out demons and other unclean spirits is given priority (Jesus gave them authority over unclean spirits). Casting out unclean spirits was an important part of Jesus’ mission. The kingdom of God which Jesus was proclaiming is a world where fullness of life is present. It is a world where happiness, good health, peace, and harmony are found. In such a world, there can be no room for unclean spirits and demons, for these spirits represent the absence of goodness and fullness of life. In both Jesus’ and the evangelist Mark’s time, unclean spirits and demons were believed to be the origin and cause of all illnesses. As such, to ensure that the community enjoyed happiness, good heath, peace and harmony, the unclean spirits had to be completely destroyed. It is not a coincidence, therefore, that the first miracle that Jesus performs as reported by the evangelist Mark is the cure of a demoniac (cf. Mark 1:21-28). There could not have been a better way for Jesus to announce the in-breaking of the kingdom of God than to free a man from a demonic possession.
But there is another equally important reason why casting out evil spirits was given such a priority by Jesus. Jesus’ mission had as its goal the bringing back of creation into a life of obedience to God. The fullness of life which is the content of the good news of the kingdom of God proclaimed by Jesus and entrusted to the twelve could only be realized when creation has once again learnt to listen to the voice of God. In the Genesis account of the fall, Adam and Eve found themselves ousted from the garden of life (and subsequently from God’s life-giving presence) when they chose to listen and believe the lies of Satan. Satan is hostile to God and is always out to frustrate God’s plans. Because Satan is cunningly perceptive, he was able to have Adam and Eve believe his lies. Jesus’ mission of bringing creation back into God’s obedience cannot be successful if Satan continues to fill the hearts of men and women with lies. By casting out demons, Jesus was ridding the world of the instigators of lies, thus making it easy for men and women to remain obedient to God. This is part of the good news with which the twelve were entrusted. It is the good news in which we rejoice.