Look at the connection between [1 Thessalonians] 3:12 and 3:13.
12) May the Lord cause you to increase and abound in love for one another, and for all men, just as we also do for you; 13) so that he may establish your hearts unblamable in holiness . . .
If God causes them to abound in love, they will have the holiness they need to meet the Lord. I infer from this that love is the essence of holiness. And that means, then, that the covenant requirement of holiness is also a gift as well as a command, because the love that is the heart of holiness is a gift and a command. Paul wants the church to be holy and so he prays: Lord cause them to abound in love so that they will be holy. You have promised in the new covenant to write your holy law on our hearts. You have promised in the new covenant to give us the Spirit and cause us to walk in your holy statutes. So, Lord, do it now, and do it by making love increase and abound.