Christians tend to focus on sin instead of salvation when engaging others in conversation. When we do this, we instantly put up walls between us and the individual that we are trying to reach. Until we can reach someone with the Gospel, their sins become irrelevant. I am not trying to dismiss accountability of others or the seriousness of sin. What I am saying is that until someone believes in the Gospel, they are not going to be open to you criticizing their behavior.
We should not focus on sin because sin is a product of behavior counter to what God has designed. If the person that you are confronting does not believe in the gift of eternal life through Jesus, then they will not understand their sinful behavior. Some of the most significant issues that I see Christians dwelling on are homosexuality and abortion. For some reason, Christians want to attack the product of bad behavior instead of addressing the real problem.
Homosexual marriage is counter to what the Bible tells us is God's intended design for the institution. If you take a look at Genesis, God lays out what his definition is for marriage.
Genesis 2:24 NASB 24 For this reason a man shall leave his father and his mother, and be joined to his wife; and they shall become one flesh.
Nowhere in the Bible does it say a man shall be joined to his husband or a woman shall be joined to her wife. Our secular society is trying to redefine what marriage is. The cause of many marital problems is a break down in the family unit as defined by God. When a sin takes place, it is a cause of a problem. The effect is the problems that we see in society.
If you look at the issue of abortion, the same thing can be concluded. The sin of abortion was created at conception. The repercussion of the sin is the act of the abortion itself. If the original circumstances that caused the pregnancy did not happen, then the abortion would not even be discussed.
Christians focus on sin, and their message gets lost.
Like my two examples above showed, Christians are quick to point out the sin in others. Instead of wasting our efforts on the problem, we should be focusing on the cause. The cause of sin is a disobedience of God. God has laid out his expectations in the Bible. Sometimes we know what the Bible says and choose to do another. Other times people do not see the truth of God. When you do not see the truth because of your lack of knowledge, you will end up stumbling all of the time.
When we focus on sin instead of the Gospel, nothing is going to get accomplished. Until someone accepts the Gospel, that person will turn a deaf ear to your criticism.
After someone crosses the line of faith, it is good to hold each other accountable as brothers and sisters in Christ. Until your relationship with the other person has the same spiritual foundation as yourself, stick to what Jesus instructed his disciples to do.
Mark 16:15-16 NASB 15 And He said to them, “Go into all the world and preach the gospel to all creation. 16 He who has believed and has been baptized shall be saved; but he who has disbelieved shall be condemned.