Why did Jesus have His disciples administer baptism and not do it Himself?  Calvin comments, “He calls Christ’s Baptism that which He administered by the hands of others, to teach us that Baptism is not to be valued from the person of the minister, but that its whole force depends on its author, in whose name and by whose command it is administered…our Baptism has no less efficacy to cleanse and renew us than if it had been given directly by the Son of God.” (qt’d in Morris p. 252)