The readings for the fourth Sunday after Trinity are taken from Isaiah 66:10-14; Galatians 6:1-10, 14-18; and Luke 10:1-20.
At the end of a very long book, Isaiah explains that Jerusalem will have gladness and joy because God extends to her peace like a river. God will comfort His people the way a mother comforts her child.
At the end of Paul’s letter to the Galatians, He writes about restoring one another in a spirit of gentleness, bearing one another’s burdens and thus fulfilling the love of Christ among us. Paul urges us to not grow weary in doing good. Paul urges us to walk in the way of peace and mercy.
Luke records how Jesus sent out seventy other disciples to extend His kingdom of peace. Those disciples returned from their mission with joy because they witnessed the power of God’s Word and Spirit. Jesus turns their attention away from thinking about power to thinking about joy over the fact that their names are written in heaven.
God extends His kingdom of peace. That peace is the product of Jesus’ life as our substitute under the law; He bore the condemnation of the law and He fulfilled the law for every one of us. That redeeming work of Jesus produces a powerful and enduring joy which overflows (remember, Easter-tide is still rising and the Holy Spirit of Pentecost is still moving) from us to others.