On the heels of saying, "The harvest is plentiful, but the workers are few," Jesus as the Lord of the harvest sends out his twelve disciples. We're used to this harvest passage being quoted as we send out missionaries into the far corners of the earth, but here Jesus forbids the disciples from going to either the Gentiles or the Samaritans. They are only to go to the lost sheep of the house of Israel. Why? By the time Matthew wrote this Gospel, the church would have already consisted of Jew and Gentile Christians. Why risk offending the Gentile hearers of this Gospel by reporting how Jesus excluded Gentiles and Samaritans in his very first commissioning of the disciples?
I'm not sure the Gentile Christians of Matthew's day would have been offended. They would have understood that Jesus came into the world to fulfill the promise made to Israel long ago through Abraham, Isaac and Jacob, about a land where they might find everlasting rest and about being a people more numerous than the stars of the heavens. The entire history behind that promise is recorded in the story of the Old Testament: the birth of the nation of Israel, their covenant with God, how they broke that covenant repeatedly, their exile into a foreign nation, their return to a destitute land, and how God yet desired to keep the ancient promise, this time through a new covenant.
The gospel that today blesses the entire world came to us first through the promise made to the Jewish people. It should come as no surprise, then, that Jesus makes it a priority to proclaim the message of salvation to Israel. Since ancient times they had been waiting for the Messiah's arrival while the rest of the world walked in darkness. But now that the Messiah has arrived, will he find faith left among his own people?
"And as you go, preach, saying, 'The kingdom of heaven is at hand.' Heal the sick, raise the dead, cleanse the lepers, cast out demons." Jesus transfers to his disciples the authority to do everything he's been doing up until now, and I'm sure the disciples got a kick out of having such extraordinary power in their own hands. But the reason Jesus gives for sending them on this mission is meant to keep them in a humble state of mind: "Freely you received, freely give."
Usually I just gloss over this part of the passage. Yeah, yeah, freely receive, freely give, it's better to give than to receive, sure. It sounds like a moral truism you find at the end of one of Aesop's Fables. But I don't think Jesus is speaking in general terms to the disciples, as if he were saying, "Look at all that I've given you, now you go and give back to the world out there." I think he's talking about something more specific, that the reason he wants the disciples to heal the sick, raise the dead, cleanse the lepers and cast out demons is that they themselves have experienced the healing of their sickness, resurrection unto life, cleansing from leprosy, and freedom from bondage to Satan. Maybe not physically but spiritually. The sickness was in their hearts, they were dead in their sins, their spiritual leprosy had estranged them from God, and they were enslaved to the devil's will. All the healings they had witnesses up until this point were like parables of their own need for Jesus to make them whole. As Jesus' disciples they should have grasped this, and so he sends them out not to inflate their egos or give them a chance to wow the crowds, but with the understanding that they are just freely giving what they themselves have freely received.