Humility or fear of judgement?

I was listening to a sermon by John Piper in regards to the churches responsibility in confronting our brothers/sisters or "so-called brothers" (1 Corinthians 5:11) who are unrepentantly in sin. A very strong message but I was struck by this: "Humility does not try to tell God how to be gracious. It listens and tries to obey with fear and trembling." How often do I not go to a brother or sister in sin because I think "who am I to cast judgment on their actions." Although we all suffer with sin issues, we are commanded to go to one another and point each other towards Christ. Humility towards Christ should thrust us forward with fear and trembling to admonish and rebuke our brothers and exhort them in the teachings of Christ not falsely claim passive humility towards another because of our own fears and sin.

If we are in Christ, than we are being purified for his purposes. "Who [Jesus Christ] gave himself for us to redeem is from all lawlessness and to purify for himself a people for his own possession who are zealous for good works (Titus 2:14)." So those who are in Christ should look towards His purification in us. I am coming closer to the conclusion that Christ will use me in the life of others and others throughout the course of my life to sanctify me and purify me so that I might be used according to His purposes.

"If you reject Christ as a purifier, you do not have Him as a pardoner. You do not have Him as a divided Christ, He is One." (John Piper)