Some Christians like to call out other people's sin, but is that biblical? Well, it can be when done right. (As in, the way The BIble says to do it)
The Bible says we are to point out our friends' sin, but in love and humility.
"Confess your faults one to another, and pray one for another, that ye may be healed." JAMES 5:16
"Brethren, if a man be overtaken in a fault, ye which are spiritual, restore such an one in the spirit of meekness; considering thyself, lest thou also be tempted." GALATIONS 6:1
What that means is, we tell them, "I've noticed this and I'm worried you're headed down a bad road. Can we talk about it? Can we pray about it? How can I help you through this? How can I be an example of Christ for you?
The reason for calling them out isn't to condem them, but to raise them up in love. That is what we are called to do.
A very powerful verse comes to mind in this situation. One verse many people forget. This verse is the reason I have never called a friend out.
"And why beholdest thou the mote that is in thy brother's eye, but considerest not the beam that is in thy own eye?" MATTHEW 7:3
It's tempting to want to point out people's faults, but unless we don't struggle with that sin, is it our place? If I struggle with self indulgence and gluttony, how can I point out gluttony in a friend? What if I'm thinner (so I don't struggle with it as much) but it's still a sin of mine? Can I call out my friend because I think my sin is less than hers??? No!!!!!!! That's self-righteous and hypicritical!!! You can however say, "This is something I struggle with, and I think you struggle too. Can we lift each other up and encourage each other and try not to do that sin?"
If we aren't going to love them through it, then we do nothing but slander them and hurt them, and that is NOT biblical!!! Beware of self-rigteousness! Remember that verse earlier about calling out sin, well go just a little further and it says this:
"For if a man think himself to be something, when he is nothing, he deceiveth himself." GALATIONS 6:3
If you say, "this is your sin and the reason I can't be your friend." You miss the big picture entirely. And you miss out on the biblical blessing that comes from calling out sin.
The blessing of pointing out a friend's sin, and then loving them through it is, YOU GET TO WATCH THEM GROW!!!!! If they are truly a Christian, then they will want to grow. But if you point out their sins and walk away, you miss out on a blessing and most likely will be fighting your own self-righteous sins.