It’s simple. When you’re sure it would offend God’s law to do something or to refrain from doing something, you should choose to follow God’s law regardless of the opposition or consequences.
The difficult part is being sure of what God’s law requires us to do or to refrain from doing. Each of us is responsible for making decisions about how to live our own lives, and we must apply the teachings of the Bible to those decisions as best we can. Parents also have a duty to instruct their children in God’s law and those children have a duty to obey their parents (Ephesians 6:104). In addition, we are instructed to teach our fellow Christians to follow God’s law and to strive for righteousness within our local churches (1 Corinthians 5; 2 Timothy 4:2).
Outside the church is a different matter. Jesus refused to condemn a woman caught in adultery, and he shared the gospel with another woman living with a man she wasn’t married to (John 8:1-11; John 4:7-26). Stephen prayed for forgiveness for men who were stoning him to death (Acts 7:54-60). And in the same chapter where Paul says to not even eat with an unrepentant, sinful man within the Corinthian church, he declares: “What business is it of mine to judge those outside the church? Are you not to judge those inside? God will judge those outside” (1 Corinthians 5:12-13).
So what is a Christian to do when in the course of his work “outside the church” he is asked to do something which would enable another person to do something in violation of God’s law? Should he pay for his employees’ medical insurance which might make it possible for a woman to have an abortion? Should he provide medication which a patient can take to commit suicide? Should he (or she) issue a marriage license to a couple so they can enter a same-sex marriage? Are these things just part of doing business in a secular culture – similar to eating meat that was sacrificed to a pagan idol? Or at some point do they cross a line and involve the Christian directly in the bloody pagan rituals? (Read 1 Corinthians 8 and 10 if you didn’t understand that reference.)
That is the difficult part and something Christians and churches need to seriously consider, often on a case-by-case basis. Something else they need to seriously consider is whether they are really concerned with following God’s law or if they are being motivated by something else, such as fear of or hatred toward people who are different from them. After all there are many things which offend God’s law, including remarriage after a divorce, but I’ve never heard of a clerk refusing to issue a license to a divorcee entering a second or third marriage (Matthew 19:8-9).
““Why do you look at the speck of sawdust in your brother’s eye and pay no attention to the plank in your own eye? How can you say to your brother, ‘Let me take the speck out of your eye,’ when all the time there is a plank in your own eye?” (Matthew 7:3-4).