Many Christians today feel it better to remain silent in the sight of other’s sin, rather than speaking up and confronting a fellow believer.
We are commanded in Scripture to speak up and even to ‘rebuke’ our neighbor so that we might not be guilty of sin. “You shall not hate your brother in your heart. You shall surely rebuke your neighbor, and not bear sin because of him.” (Leviticus 19:17, and also Ezekiel 33:8-9)
We shouldn’t be fearful of what people might think or how they might react if we approach them to confront them with sin.
Yes, it is important to adhere to Jesus’ words and not cast judgment on other people for things we ourselves are guilty of. Jesus did not say that we should not approach our neighbor at all and point out their sin, but rather that we should “first cast out the beam out of thine own eye; and then shalt thou see clearly to cast out the mote out of thy brother's eye.” (Matthew 7:1-5)
In essence, if you don’t tell someone the truth because you are fearful of their reaction, or you are fearful that they might hate you, then you are not operating in love for your neighbor.
People would often put their lives at risk to save the lives of strangers, but when it comes to spiritual matters and eternal life or death, we will hide and say that we’d rather not get involved. We’re too afraid to stick our neck out, or confront another person. We would rather let that other person die and go to hell, rather than take criticism, or retaliation.
But the Bible says that we should rebuke in any way possible.
Don’t be afraid to speak up. Approach the person with love, but speak the truth. When you fail to tell someone the person the truth because you are afraid they will reject you and or the Gospel, then you have rejected it for them. That other person has the right to make that decision and you need to give them the opportunity to make it for themselves, whatever the issue might be.
Speak up in love, and let the Holy Spirit do the rest.