The readings for Pentecost 15 are taken from Ezekiel 33:7-9; Romans 13:1-10; and Matthew 18:1-20.
Ezekiel records how God made him a watchman and sternly warned Ezekiel to warn the people. God held him responsible for warning the people and that removed any excuse the people might make for continuing in their wicked ways.
Paul was a watchman who has many warnings for us in the letter to the Romans. This passage reminds us that God appoints watchmen for our physical lives in the world, whom we are to support with respect and taxes. Most of all, we must owe no one anything but love. Ezekiel loved Israel as a faithful watchman and Jesus loved us all by giving His life and Word to us.
In the lesson from Matthew, Jesus warns us against the perils of our corrupt human nature, especially vanity. The sternest of all warnings is to make sure that nothing in our lives causes us to sin and to make sure that nothing in our lives causes anyone else to sin, especially children. Jesus is being literal to indicate how hard it is to cut what causes sin out of our lives . . . like cutting off a hand or foot. But it is the heart that causes sin (see Mark 7) and God provides a new heart for us (see Ezekiel 36:24ff). Jesus follows these stern warnings with the only remedy for our failure. The Lord Jesus seeks us out and brings us home on His shoulders, referring to His comprehensive redeeming work for body and soul. The Good Shepherd not only dies for the sheep, but even for the wolf in each of us.