Do not judge your brother!
Each one therefore ought only to judge himself, and to be on the watch, with care and circumspection in all things
I plainly discovered that a monk was in the same case and entangled in the same faults for which he had ventured to judge others. Each one therefore ought only to judge himself, and to be on the watch, with care and circumspection in all things not to judge the life and conduct of others in accordance with the Apostle's charge, "But thou, why dost thou judge thy brother? to his own master he standeth or falleth." (Rom 14:10.4) And this: "Judge not, that ye be not judged. For with what judgment ye judge, ye shall be judged." (Mt 7:1-2) For besides the reason of which we have spoken, it is for this cause also dangerous to judge concerning others because in those matters in which we are offended - as we do not know the need or the reason for which they are really acting either rightly in the sight of God, or at any rate in a pardonable manner - we are found to have judged them rashly and in this commit no light sin, by forming an opinion of our brethren different from what we ought.
John Cassian, Institutes of the Coenobia V,30