Love Fulfills the Law; Wake and Put on Christ
Paul returns from civic obligations to the debt that can never be fully discharged: love one another. He cites neighbor-directed commandments from the Decalogue and gathers them under Leviticus 19:18, “Thou shalt love thy neighbour as thyself.” Love does no harm to the neighbor and therefore fulfills the law’s interpersonal aim.
The paragraph then turns eschatological. Salvation is nearer than when believers first believed; the night is far spent and the day is near. They must cast off works of darkness, put on the armor of light, and finally “put ye on the Lord Jesus Christ.” The wakefulness/light/armor imagery closely parallels 1 Thessalonians 5.