Judge or condemn?
Luke
Chapter 12
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1 Meanwhile, so many people were crowding together that they were trampling one another underfoot. He began to speak, first to his disciples, "Beware of the leaven--that is, the hypocrisy--of the Pharisees.
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2 "There is nothing concealed that will not be revealed, nor secret that will not be known.
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Therefore whatever you have said in the darkness will be heard in the light, and what you have whispered behind closed doors will be proclaimed on the housetops.
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I tell you, my friends, do not be afraid of those who kill the body but after that can do no more.....
http://www.usccb.org/nab/bible/luke/luke12.htm
One of the Greatest Loves you can do for a "Lost" Brother or Sister is to try to get them to see condition of Sin and their Need of Jesus Christ for forgiveness of Sins and reconciliation to God.
Jesus didn't tell us to be quiet:
Luke
Chapter 12
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I tell you, everyone who acknowledges me before others the Son of Man will acknowledge before the angels of God.
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But whoever denies me before others will be denied before the angels of God.
http://www.usccb.org/nab/bible/luke/luke12.htm
Ephesians
Chapter 5
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Try to learn what is pleasing to the Lord.
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Take no part in the fruitless works of darkness; rather expose them,
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for it is shameful even to mention the things done by them in secret;
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but everything exposed by the light becomes visible,
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for everything that becomes visible is light. Therefore, it says: "Awake, O sleeper, and arise from the dead, and Christ will give you light." 3
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4 Watch carefully then how you live, not as foolish persons but as wise,
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making the most of the opportunity, because the days are evil.
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Therefore, do not continue in ignorance, but try to understand what is the will of the Lord.
http://www.usccb.org/nab/bible/ephesians/ephesians5.htm
We are to try to help save the Lost Souls:
James
Chapter 5
13
Is anyone among you suffering? He should pray. Is anyone in good spirits? He should sing praise.
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Is anyone among you sick? 6 He should summon the presbyters of the church, and they should pray over him and anoint (him) with oil in the name of the Lord,
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and the prayer of faith will save the sick person, and the Lord will raise him up. If he has committed any sins, he will be forgiven. 7
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Therefore, confess your sins to one another and pray for one another, that you may be healed. The fervent prayer of a righteous person is very powerful.
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Elijah was a human being like us; yet he prayed earnestly that it might not rain, and for three years and six months it did not rain upon the land.
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Then he prayed again, and the sky gave rain and the earth produced its fruit.
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My brothers, if anyone among you should stray from the truth and someone bring him back,
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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.
http://www.usccb.org/nab/bible/james/james5.htm