Thomas a Kempis, The Imitation of Christ 1.16

Of bearing with the faults of others

1. Those things which a man cannot amend in himself or in others, he ought patiently to bear, until God shall otherwise ordain. Bethink you that perhaps it is better for your trial and patience, without which our merits are but little worth. Nevertheless you ought, when you find such impediments, to beseech God that He would vouchsafe to sustain you, that you be able to bear them with a good will.

2. If one who is once or twice admonished refuses to hearken, strive not with him, but commit all to God, that His will may be done and His honor be shown in His servants, for He knows well how to convert the evil unto good. Endeavor to be patient in bearing with other men's faults and infirmities whatsoever they be, for you yourself also have many things which have need to be borne with by others. If you cannot make your own self what you desire, how shall you be able to fashion another to your own liking? We are ready to see others made perfect, and yet we do not amend our own shortcomings.

3. We will that others be immediately corrected, but we will not be corrected ourselves. The freedom of others displeases us, but we are dissatisfied that our own wishes shall be denied us. We desire rules to be made restraining others, but by no means will we suffer ourselves to be restrained. Thus therefore does it plainly appear how seldom we weigh our neighbor in the same balance with ourselves. If all men were perfect, what then should we have to suffer from others for God?

4. But now has God thus ordained, that we may learn to bear one another's burdens, because none is without defect, none without a burden, none sufficient of himself, none wise enough of himself; but it behooves us to bear with one another, to comfort one another, to help, instruct, admonish one another. How much strength each man has is best proved by occasions of adversity: for such occasions do not make a man frail, but show of what temper he is.