God gives us a clear answer [to the above question] through the words of St Paul in 1 Corinthians. First, in chapter 6, Paul lists a number of sins that bring condemnation to those who won’t repent of them, including idolatry, drunkenness and homosexuality. Then, in chapter 13, Paul states that ‘love does not rejoice at wrongdoing, but rejoices with the truth.’ In other words, when you see someone engaging in sin, it’s not loving to help and support them in that act or to give him the impression that what he is doing it good, right and salutary.
So if you want to love your neighbor with same-sex attraction, you don’t love him by cheering him on as he seeks out a kind of union that God has called sinful, … Rather, you love him by warning him of the danger that this sin brings to his soul and by confessing the love and mercy and forgiveness that Jesus Christ gives to all who repent of their sins and hunger for His righteousness.
And, of course, this principle applies to countless issues beyond that of same-sex marriage. If a woman learns that her son intends to leave his wife, that woman manifests the love of God not by urging her son to follow the desires of his sinful heart but by urging him to follow God’s command to be a faithful husband. If a Christian want to love his Muslim neighbor, he does it by confessing to him what’s true, that Jesus Christ, the Son of God, died for his sins. He doesn’t do it by bowing his head and praying with the Muslim neighbor when he offers up praises to his false god. If a Christian woman wants to love her alcoholic friend, she does it by helping her get sober, not by supplying her with vodka. …
No matter how often people tell us that by opposing same-sex marriage we are opposing love, the truth is that love is God’s word, which means that God gets to decide what love means. And because the world’s understanding of love is corrupted and false, the world’s love will one day crumble. But because God is the author of love, in the end, God’s love wins.
Source: “God’s Acts of Love” by Hans Fiene in The Lutheran Witness, February 2016, p. 18-19.