Verses 9-13 deal with the importance of demonstrating love to fellow believers, and verses 14-21 broaden this responsibility to include wider application to non-believers.
"Nowhere else in Paul's writings do we find a more concise collection of ethical injunctions. In these five verses are thirteen exhortations ranging from love of Christians to hospitality for strangers. There are no finite verbs in the paragraph. There are, however, ten participles that serve as imperatives. In the three other clauses (vv. 9, 10, 11) an imperative must be supplied. Each of the thirteen exhortations could serve as the text for a full-length sermon. What they deal with are basic to effective Christian living."366
12:9 Love is of primary importance (cf. Lev. 19:18; Matt. 22:39; 1 Cor. 13). However it must be sincere (cf. 1 John 4:19-21). This command acts as a heading for this whole list of exhortations.
"Paul is not always talking specifically about love, but he keeps coming back to love as the single most important criterion for approved Christian behavior."367
The totally committed Christian should hate evil and love what is good as his Lord does expressing commitment to His attitudes as well as to His actions.
"What God seeks in the believer is not so much a single worthy act as it is a continuing quality of life."368
12:10 We need to express love to individual people as well as to ideals (v. 9). Giving recognition and appreciation to those who deserve it is a concrete way of expressing love.
12:11 It is natural for Christians to slack off in our diligence in serving the Lord when we have been Christians for some time. Apollos was a model of someone who maintained fervent diligence in his service (Acts 18:25; cf. Rev. 3:15-16).
12:12 We must never lose sight of our hope of things in the future that God has promised us. This will help us persevere in tribulation (cf. 5:3-4). Prayer is our great resource whenever we feel stress and strain (cf. Phil. 4:6-7). Note the same progression from hope to perseverance to prayer in 8:24-27.
12:13 We should never be so self-centered that we fail to reach out to others. Again God the Father and God the Son are our great examples here.
12:14 Paul repeated Jesus' instruction here (Matt. 5:44; Luke 6:27-28). To persecute means to pursue. Blessing involves both wishing God's best on people and praying for them.
"The principle of nonretaliation for personal injury permeates the entire New Testament."369
12:15 Believers should share the joys and sorrows of their neighbors, especially fellow believers (1 Cor. 12:26; Phil. 4:13).
12:16 The first part of this verse means "Have equal regard for one another"(NEB). Feelings of superiority are neither realistic nor appropriate for those who owe all to God's grace.
12:17 The second exhortation probably means that we should give thought to how we do what is right so our witness may be most effective to believers and unbelievers alike (cf. Col. 4:5; 1 Tim. 3:7).
12:18 Paul strongly advocated being a peacemaker (cf. Matt. 5:9), but he did not promote peace at any price. In some situations, peace might give way to conflict if, for example, the truth is at stake. Notwithstanding the believer should not be the instigator of trouble under normal circumstances. Note Paul's two qualifiers regarding living at peace in this verse.
12:19 If hostility does erupt, the Christian should not retaliate. Rather he or she should trust God to right the wrong (cf. 1 Sam. 24-26). Long ago God promised to take care of His people when others wronged them (Deut. 32:35).
12:20 Instead of doing one's enemy an unkindness the believer should do him or her positive good (cf. Matt. 5:44). This may result in the antagonist acknowledging his error and even turning to God in repentance. Heaping burning coals on his head figuratively describes doing good that results in the conviction and shame of the enemy. The expression alludes to the old custom of carrying burning coals in a pan. When one's fire went out at home, a person would have to go to a neighbor and request hot coals that he or she would then carry home on the head. Carrying the coals involved some danger, discomfort, and uneasiness for the person carrying them. Nevertheless they were the evidence of the neighbor's love. Likewise the person who receives good for evil feels uncomfortable because of his neighbor's love. This guilt may convict the wrongdoer of his or her ways in a gentle manner.
12:21 Paul again concluded with a summary. Being overcome by evil means giving in to the temptation to pay back evil for evil. When people do wrong, they expect to receive evil from those they have wronged. When they receive kindness instead, their hard hearts often become softer.
There is a progression in 12:9-21. Paul progressed from the Christian's duty to his fellow believers to action that would affect non-Christians as well. However all that Paul wrote in 12:3-21 is directly applicable to life within the body of Christ. The believer may encounter enemies there as well as in the world.
The general nature of the commands in this pericope illustrates the essentially gracious character of the Law of Christ (Gal. 6:2) under which Christians now live. Compare this with the legal nature of the commands in the Mosaic Law (cf. 10:4). God gave the Israelites many explicit commands about how they were to behave in a multitude of specific situations. The commands in verses 9-21, as well as in all the New Testament, are much more general and are similar to principles. This is one reason we say the Israelites lived under "law"and we live under "grace."
