Eczekial 3:1819
If I say to the wicked, you shall surely die, and you give him no warning, nor speak to warn the wicked from his wicked way, in order to save his life, that wicked man shall die in his iniquity; but his blood I will required at your hand. But if you warn the wicked and he does not turn from his wickedness or from his wicked way, he shall die in his iniquity; but you will have saved your life.
James 5:19-20
My brothers, if anyone among you should stray from the truth and someone bring him back, he should know that whoever brings back a sinner from the error of his way will save his soul from death and will cover a multitude of sins.
But as so many of you have stated, prudence must be exercised. We must allow the Holy Spirit to guide us in these delicate matters.