The story we hear this week from Luke’s gospel is about Jesus sending seventy out ahead of him. This was a kind of “internship,” training time while Jesus was still with them. The mission was the same as Jesus’ own ministry: “cure the sick” and “say to them, ‘the kingdom of God has come near to you.’”
Jesus sends them ahead to every town and place where he was heading himself. He was on his way to Jerusalem and would likely travel through villages where he had not been before. Rumours of what Jesus was doing had undoubtedly spread into Samaria so the seventy will announce his coming by giving people a preview of his own work.
They are to travel “in pairs”, which we can assume is for safety and for mutual encouragement. If you have to do something dangerous or risky you want to have somebody with you. It’s also a sign that “we’re in this together” as followers of Jesus.