Mark 6:7, 12-13

And He called the twelve [disciples] and began to send them out [as His special messengers] two by two, and gave them authority and power over the unclean spirits.

So they went out and preached that men should repent [that is, think differently, recognize sin, turn away from it, and live changed lives]. And they were casting out many demons and were anointing with oil many who were sick, and healing them.