"Let love be genuine. Abhor what is evil; hold fast to what is good."
Scripture tells us that "God is love" (1 John 4:7-8). Of course, there is a great deal of confusion in our day as to what love means, so there are all manner of false understandings of the love of God both in the church and the world. A true understanding of divine love must take into account all of the Lord's other attributes, including His holiness and justice. In His love, God does not overlook sin, and we are constrained by His love to be holy as He is holy (1 Peter 1:8, 13-21). A true understanding of God's love will not compromise His holiness for the sake of a love that makes no demands of the beloved.
Because love is one of God's attributes, any understanding of what it means to be made in His image and to live in a way that pleases Him must take love into account. After all, though we are fallen, we still bear the image of our Creator, and we are being transformed into the image of Christ, who is Himself the perfect image of God (Gen. 1:26-27; 2 Cor. 3:18; Col. 1:15). We find it no surprise, therefore, that Paul includes a discussion of love in his description of what the life of people being transformed by God's Spirit looks like.
Romans 12:9a tells us that our love must "be genuine." This idea seems simple enough, and we can hardly do better than Dr. R.C. Sproul's comments on verse 9a in his commentary Romans: "God expects from us authentic love, that which is not mixed with hypocrisy or false sentiment." Genuine love does not make a show of affection that is not rooted in the realities of the heart. While it is good to treat people kindly and to love them in such a way that we go the extra mile for them, we have not truly pleased the Lord with such actions if we harbor hatred in our heart for them all the while we do such things (Matt. 5:21-26, 38-48).
Importantly, today's passage seems to serve as a section heading for what follows in the rest of Romans 12. In other words, the admonitions in verses 9b-21 define what genuine love means. Understanding what the Apostle teaches in these verses will help us know what true love looks like and keep us from succumbing to the false ideas of love present in our own culture. Verse 9b indicates that we are to "abhor what is evil; hold fast to what is good." We see here that love does not lead us to do what is wrong. Many people justify all sorts of illicit relationships in the name of love. However, even if we "feel" like we are in love or "feel" like we are showing love, we do not experience godly love if we engage in something God forbids in His law.
Coram Deo
Today we see a false understanding of love manifested most commonly in romantic relationships. Many people justify adultery by saying that they no longer love their spouse but love another person. People often justify homosexual relationships by saying, "As long as two people love each other, their genders do not matter." But God says that adultery, homosexual partnerships, and many other relationships are evil, and those engaging in them are not practicing true love.