There is a discussion about whether a Christian should care about whether someone is sinning or not, and if so, what should they do.
We must recognize that Jesus said the words “Do not judge” but we have to look at the context to know what he was really saying.
Jesus told us that we will be judged in the same way we judge others. Jesus was saying to be merciful, loving, and to not be a hypocrite. But we are to help others who have sin in their lives. To do this in love and with mercy, we must handle a given sin in our own lives before we try to address it in someone else. If you take care of that sin in your own life first, you can see clearly to help someone deal with it in their lives.
“Do not judge so that you will not be judged. 2 For in the way you judge, you will be judged; and by your standard of measure, it will be measured to you. 3 Why do you look at the speck that is in your brother’s eye, but do not notice the log that is in your own eye? 4 Or how can you say to your brother, ‘Let me take the speck out of your eye,’ and behold, the log is in your own eye? 5 You hypocrite, first take the log out of your own eye, and then you will see clearly to take the speck out of your brother’s eye.
We see this more clearly in Luke 6:27-45
27 “But I say to you who hear, love your enemies, do good to those who hate you, 28 bless those who curse you, pray for those who mistreat you. 29 Whoever hits you on the cheek, offer him the other also; and whoever takes away your coat, do not withhold your shirt from him either. 30 Give to everyone who asks of you, and whoever takes away what is yours, do not demand it back. 31 Treat others the same way you want them to treat you. 32 If you love those who love you, what credit is that to you? For even sinners love those who love them. 33 If you do good to those who do good to you, what credit is that to you? For even sinners do the same. 34 If you lend to those from whom you expect to receive, what credit is that to you? Even sinners lend to sinners in order to receive back the same amount. 35 But love your enemies, and do good, and lend, expecting nothing in return; and your reward will be great, and you will be sons of the Most High; for He Himself is kind to ungrateful and evil men. 36 Be merciful, just as your Father is merciful.
37 “Do not judge, and you will not be judged; and do not condemn, and you will not be condemned; pardon, and you will be pardoned. 38 Give, and it will be given to you. They will pour into your lap a good measure—pressed down, shaken together, and running over. For by your standard of measure it will be measured to you in return.”
39 And He also spoke a parable to them: “A blind man cannot guide a blind man, can he? Will they not both fall into a pit? 40 A pupil is not above his teacher; but everyone, after he has been fully trained, will be like his teacher. 41 Why do you look at the speck that is in your brother’s eye, but do not notice the log that is in your own eye? 42 Or how can you say to your brother, ‘Brother, let me take out the speck that is in your eye,’ when you yourself do not see the log that is in your own eye? You hypocrite, first take the log out of your own eye, and then you will see clearly to take out the speck that is in your brother’s eye. 43 For there is no good tree which produces bad fruit, nor, on the other hand, a bad tree which produces good fruit. 44 For each tree is known by its own fruit. For men do not gather figs from thorns, nor do they pick grapes from a briar bush. 45 The good man out of the good treasure of his heart brings forth what is good; and the evil man out of the evil treasure brings forth what is evil; for his mouth speaks from that which fills his heart.
Jesus was clear we ARE to judge – but with righteous judgment.
1 He said to His disciples, “It is inevitable that stumbling blocks come, but woe to him through whom they come! 2 It would be better for him if a millstone were hung around his neck and he were thrown into the sea, than that he would cause one of these little ones to stumble. 3 Be on your guard! If your brother sins, rebuke him; and if he repents, forgive him. 4 And if he sins against you seven times a day, and returns to you seven times, saying, ‘I repent,’ forgive him.”
19 Do not receive an accusation against an elder except on the basis of two or three witnesses. 20 Those who continue in sin, rebuke in the presence of all, so that the rest also will be fearful of sinning.
Paul had someone kicked out of the church because they were sinning in 1 Cor 5. See in verses 12-13 how we are to judge those within the church:
12 For what have I to do with judging outsiders? Do you not judge those who are within the church? 13 But those who are outside, God judges. Remove the wicked man from among yourselves.
But that same passage tells us to not judge those outside the church. If people are sinning and they do not claim to be Christians, then let it alone. But if they DO claim to be Christians, then address it.
God has told us how to deal with people who are in sin. He said we must challenge people who claim to be Christians and if they repent, then forgive them. But if they do not, go to them with two or three people. If they still do not repent, take it to the church. If they still do not repent, then remove them from the church and have nothing to do with them. However, if at any point they repent, we are to forgive them, and if they had been put out of the church, invite them back in.