Just as Paul cannot help breaking out in poetic tribute to love in his famous love chapter, 1 Corinthians 13, after beginning the subject of spiritual gifts in 1 Corinthians 12, so also he does the same in Romans 12.
After discussing how God has gifted various church members with faith appropriate for different roles in the church, Paul offers a poetic composition on how love reaches for the common good in the church. Our translations do not catch all the words that have love in the opening verses of this section. The section begins with the heading, Let love be genuine. This is as if to say, Love others authentically and genuinely! The next verse, Romans 12:10, literally begins by saying, In brotherly/sisterly love be lovingly affectionate. Of course many of the specific commands give practical, detailed ways for loving others. Verse 13 ends with the phrase pursuing hospitality, but Paul's word for hospitality is literally love of stranger. So there is a lot of love language here!
Our example for how to love is Jesus. Paul's words to bless those who persecute you, bless and do not curse in verse 14 sound a lot like what Jesus says in Matthew 5:44, Love your enemies and pray for those who persecute you, or what he says in Luke 6:28, Bless those who curse you, pray for those who abuse you. There are other allusions to sayings of Jesus in the rest of chapter 13, and Jesus' love for others at the cross is stressed in Romans 15:1-3. So Paul is hinting that to love genuinely is to love as Jesus loved. And our paragraph doesn't just say "Love others more," it describes very specific behaviors for loving others.
Did you know that good distance runners don't just play general messages in their minds like "Relax!" or "Stay loose!" while running? Instead, good runners play very specific messages over and over in their minds, like "Let lower lip sag!" or "Feel how loose my fingers are right now!" These specific messages help their whole body to relax and stay loose.
It is the same with Paul's ideas for genuine Christ-like love in Romans 12:9-21. He is giving us very specific ideas for authentic love. For example, he says, "Rejoice with those who rejoice, weep with those who weep" (12:15), or "If it is possible, so far as it depends on you, live peaceably with all" (12:18). Another very specific idea for love is found in the quotation from Proverbs 25:21-22 to feed and give something to drink to hungry and thirsty enemies. Of course, this does not endorse playing along with abusive strategies that arise in some dysfunctional relationships. It means to think about and to help meet others' genuine needs, including the needs of people who do not like us. But what's the point of the result; "By doing this you will heap burning coals on their heads" (Romans 12:20; Proverbs 25:22)? Students of this text differ regarding whether this means that by doing good to an enemy you will increase God's judgment on the person or whether it means that by doing good you will help the person repent. The latter is much more likely, since it fits with the profound theme in this immediate section that we are not to have any part in repaying evil in our personal relationships and it fits with the overarching theme that love is to be genuine. My love for an enemy isn't genuine if I am motivated by the idea that any kindness shown increases God's punishment on the person!
Genuine love is the deepest theme in this section of Romans. At a more surface level, there is a theme of good and evil that operates throughout this text. Notice how "hate what is evil, hold fast to what is good" follows immediately after the opening title of "Let love be genuine." Then the good and evil theme is explicitly mentioned at the end of the text: "Do not be overcome by evil, but overcome evil with good" (12:21). This helps us see that genuine love is not just being nice to people. Genuine love has a moral orientation toward the good. When we show love toward someone, we are moving them toward God's goodness. To love someone is not simply to cater to specific likes and dislikes of that person. It is rather to act toward them in ways that help them experience more of God's goodness.
In the following chapter, there is a parenthetical explanation of how God can use government to repay evil for evil. But the idea of genuine love that Paul begins with in 12:9 continues to operate through Paul's emphasis on the love commandment in 13:8-10. It even extends into how Paul emphasizes love within the church divisions he addresses (14:15; 15:1-2, 7). So often we think that the letter of Romans is all about doctrine, or justification by faith. Here, though, as Paul is beginning to head toward the conclusion of the letter, we see once again that the Christian life for him is all about faith working through love (Galatians 5:6). Let love be genuine!