When Jesus had called the Twelve together, he gave them power and authority to drive out all demons and to cure diseases, and he sent them out to preach the kingdom of God and to heal the sick. (Luke 9:1-2)

This preaching is once again to kerusso: proclaim and act as a herald.

The Greek translated as "heal the sick" can also mean to make whole.

In Hellenistic medicine disease was explained as divine punishment, demonic possession, or as an imbalance of the humors: phlegm, blood, yellow bile, and black bile.

By addressing a deficit or surplus of a humor the body could be restored to balance and thereby to health. In the spiritual teaching of Jesus we might perceive a similar therapeutic approach.

By addressing a deficit or surplus of faith (self-reliance being the deficit and self-righteousness the surplus) Jesus sought to restore balance to our relationship with God and thereby to our lives.

The authority referenced in verse 1 is exousia. The Greek conforms with what we typically think of as authority. But the foundation of this authority is the ability to choose. This is the authority of a free person to decide for oneself between various alternatives.