Under the old covenant God gave His people the mark of circumcision to set them apart as His people. but the writer of Hebrews tells us that Jesus has now come, with a far superior mission, as a superior mediator or agent of a better covenant based on better promises. There is a sign, and mark for that covenant as well. To those born into the new covenant God has given us baptism, and the apostle Paul wants his Colossian friends, and us to know exactly how much that symbol should mean in our Christian life.