Paul concludes many of his letters with a “mixed bag” of closing advice and admonitions, and this passage is an example of that sort of collection. It’s difficult to deal with this assortment of disparate sayings as a unified whole; each piece of advice is more or less distinct. Two excerpts, however, lend themselves to consideration during Advent: either one may explain why the lectionary editors chose this passage for this week. V. 16 (one of the shortest verses in the Bible) says, “Rejoice always” – always an appropriate thought for Advent. V. 23 says, “May the God of peace himself sanctify you entirely; and may your spirit and soul and body be kept sound and blameless at the coming of our Lord Jesus Christ.” Note that God – and not the believer – is the principal actor here. Sanctification is never a human accomplishment, but is wholly the result of God’s gracious intervention.