"May the God of hope fill you with all joy and peace in believing, so that you may abound in hope by the power of the Holy Spirit" (Romans 15:13).
In addition to being members of a community of the Spirit, the early Christians also lived under the civil authority of the Roman government. Paul sees no contradiction between obeying the laws of the land and faith in the power of God.
13:1 Christians are to obey the laws of the land because without government there is anarchy, which is the worst of all worlds to live in. That is why we can view unbelieving and even hostile civil governments as appointed by God for our good. As Jesus said, we can "Give to the emperor the things that are the emperor's, and to God the things that are God's" (Matthew 22:21; Mark 12:17; Luke 20:25).
13:2-3 There are occasions when God approves civil disobedience, as in the case of the midwives who refused to murder the baby boys in Egypt (Exodus 1:17) and the apostles who refused to stop talking about the resurrection (Acts 5:28-30). Apart from such obvious exceptions, governments do not usually make laws against loving behaviour.
13:4-5 Any kind of government needs a police force to maintain order, and that includes weapons to restrain the violent. This means that, in addition to God's wrath as the bad consequences of sin in our world (Romans 1:18-20; 2:9), there is a delegated assigning of wrath through government law enforcement.
13:6-7 Christians will be good citizens paying their share of the government, and they can give due respect to those in authority over them (so in 1 Peter 2:13-17).
13:8-10 The ten categories of moral judgment (often called the ten commandments of Moses, Exodus 20:1-17) are stated as absolute prohibitions and commands. Jesus summed these up and stated them positively in the two laws of love (Matthew 22:36-40; Mark 12:29-31; Luke 10:25-28). By way of analogy the laws of health can be stated negatively as "you must not have this or that symptom." They can also be experienced positively when we can say "I feel full of health and energy."
Here Paul shows how the last four of the ten commandments are summed up and fulfilled in the commandment to "Love your neighbour as yourself." Paul would have known that already in the Old Testament the commandment to "love your neighbour as yourself" appears in the context of not taking revenge (Leviticus 19:18). There was also a command to love resident aliens (Deuteronomy 10:18,19), and to care for orphans and widows (Deuteronomy 14:29). But he makes the point that if we love ourselves we won't harm ourselves, and if we love others in the same way we will never ignore their distress or harm them, and that is precisely the intent of all the various Old Testament laws relating to our neighbours.
To grasp the logic of this section we can contrast two models for the advent of Christ. In the commonly accepted model there was a first coming when the Son of God was born in Bethlehem. The next event to be expected is the second coming, which by now has been awaited for nearly two thousand years. In the model which we noted in 2:5 the Lord kept making advents, comings, visits and visitations throughout the Old Testament period. Some of these were to be with individuals (Genesis 3:8; 12:7; 15:1; 17:1; 28:13; 32:24; 48:3; Exodus 33:11), and similarly in the New Testament Peter and Paul experienced such comings (Acts 9:4-5; 10:13-14; 18:9; see John 14:23, 28). Other comings were in what the prophets called a "day of the Lord" to judge or deliver a nation (Genesis 11:5; Isaiah 3:18; 4:2; 7:18, 20, 21, 21; 13:6, 9; Ezekiel 7:7-12; 30:3; Joel 1:15; 2:1). In the Book of Revelation the Lord comes to churches both to judge and to bless by coming to eat and drink with them (Revelation 3:3, 11, 20).
By comparing Isaiah 13:6-13 with Matthew 24:29 it is clear that the early Christians expected a day of the Lord when Jerusalem would be destroyed in the same way as Babylon was. In both cases the portents or signs in the heaven are metaphorical of the toppling of a great city, as also happened to Jerusalem seven hundred years before (Joel 2:30). The destruction of the temple (Matthew 24:2) and the fall of Jerusalem would be in that generation (Matthew 24:34), and we know from Roman history that the end came in AD 70. The day of the Lord would include the decimation and scattering of the Pharisee and Sadducee establishment (Matthew 21:41-43; 23:35-38; 24:2). And these events would be recognized by Christians as "the sign of the Son of Man" now reigning among all nations (Matthew 24:30-31). In this case he would use the hated Romans to do the toppling.
If we adopt the first model we have to believe Paul thought the second coming and final advent was at hand (Romans 13:11), though it is still awaited after 2,000 years. The second model allows us to see the Son of God making advents again and again among the nations until his final coming to terminate our world system. And according to this model Paul is writing to the Corinthians in the very turbulent time called "the beginning of the birth pangs" (Matthew 24:8; Mark 13:8; see Isaiah 13:8). With other Christians Paul was expecting the end predicted by Jesus for that generation (Matthew 24:34; Hebrews 8:13; 10:25, 37).
Using the second model we can also situate ourselves in the tribulations and birthpangs of every day of the Lord in the history of every country of the world. And whatever troubles we face we can look to the Holy Spirit to empower us as we wait with patience for our Lord to intervene and vindicate us. This was the attitude of Christians during the persecutions that preceded the conversion of Constantine. It was also the faith of Christians in Uganda who awaited the toppling of Idi Amin, and those who led the candlelight marches in Eastern Europe which preceded the 1989 "day of the Lord" when the communist system was so suddenly toppled.
13:11 As the day of the Lord approaches it is important to be watchful (Habbakuk 2:1-4). "Keep awake therefore for you do not know on what day the Lord is coming" (Matthew 24:42). The day is nearer now than when Paul was first converted and heard of the coming "day of the Lord" from other Christians.
13:12 The works of darkness correspond to the works of the flesh, which is all that humans can do by their own power apart from the empowering of the Spirit (Galatians 5:16-21). The armor of light was defined in a later epistle as "the whole armor of God" needed to struggle against "the cosmic powers of this present darkness" (Ephesians 6:11-12). And that armor includes both "the sword of the Spirit" and prayer in the Spirit (Ephesians 6:17-18).
13:13-14 To avoid the debauchery of the world Paul tells us to "put on the Lord Jesus Christ." Some interpret this as beating down our unruly instincts as we valiantly try to be Christlike. The contrast which we have found throughout the epistle suggests that instead of focusing our mind on what our flesh demands, we set our mind on the Spirit that empowered Jesus in his life and ministry (8:3-6).