I would have to say that if conservative Christianity is guilty of a major sin besides ignorant idolatry it is the sin of judging others. Matthew 7 says, "Do not judge, or you too will be judged. For in the same way you judge others, you will be judged, and with the measure you use, it will be measured to you.(NIV)” But this cannot be the absent of discernment towards sin because Jesus also said to be gentle as doves but wise as serpents. And while we are told not to judge other people, we are told to rebuke sin (II Tim 2:4). I think the kind of judging that Jesus is referring to in Matthew 7 is the kind of judgment that condemns another individual for sinning. There is no greater pride than to look at another and condemn them for something you have done yourself or if you haven’t done it, it is only by the Grace of God that you haven’t. Paul reminds us in Romans 2 that if we do the same things we will certainly be judged ourselves.
So what is the difference between Biblical rebuke and judging others? Both require judgment in the sense of determining when sin is reigning. As far as I can tell, I think the only difference is in the aim and manner in which it is carried out. Are we trying to build people up in their knowledge of God and their personal walks or are we thinking negatively so as to condemn them? Rebuking must be done in total humility and out of a genuine concern for the sinning individual.
Some will claim that we should not try to play the Holy Spirit but rather just love everyone. I really can’t disagree with that statement. We have problems when everyone is going around placing expectations on other Christians based on their perceptions of sin and spirituality that may or may not be biblical in reality. Granted, if the Holy Spirit isn’t doing this work then nothing will be effective. But on the other hand, we can't let sin reign in the name of love. That isn't love at all. 2 Peter says, for by what a man is overcome, by this he is enslaved. When it comes to the things that are clearly sin by Scripture, it would be the most loveless thing you could do to not try to humbly rebuke them and warn them of the danger of loving sin over God. If there are 2 possible dominions, that of sin and death or slavery to/life in Christ (Rom 6) then we ought to warn someone who we know claims to be of God but continues to play around with sin and death. Hebrews 10:26-27 If we deliberately keep on sinning after we have received the knowledge of the truth, no sacrifice for sins is left, 27 but only a fearful expectation of judgment and of raging fire that will consume the enemies of God.
I think fundamentalism is guilty of condemning the world based on unbiblical expectations in the way that Jesus is referring in Matthew 7 while evangelicals might tend to ignore biblical commands in the name of love proving that they have no love in reality. If we stick to rebuking on the clearly defined things in Scripture and do it in true humility and love aiming to build one another up in the faith, then we can’t go wrong with judging. But if we go on condemning every one for everything under the sun surely we too will be judged by God.
