Study to be patient in bearing the defects of others, because you also have many things which others must bear. We want others strictly corrected, and are not willing to be corrected ourselves. But God has so ordered it, that we may learn to bear one another's burdens, for there is no man without defect, no man sufficient for himself. We must support, comfort, help, instruct, and admonish one another. The amount of each man's virtue better appears on occasion of adversity: for the occasions do not make a man frail - they reveal what he is!
Oftentimes to we do not perceive our own inward blindness, how great it is. We often do evil, and excuse it worse. We are sometimes moved with passion and we think it to be zeal. We reprehend small things in others, and pass over great matters in ourselves. We quickly enough feel and weigh what we suffer at the hands of others; but we mind not what others suffer from us. He that well and rightly considerth his own works will find little cause to judge harshly of another.
(Thomas ‘a Kempis, The Imitation of Christ)