When your brother is disturbed and reacts to what you say to him, control your tongue lest you speak even one word in wrath and do not allow yourself to be arrogant concerning him in your heart but remember that he is your brother, a member of Christ and an image of God, influenced by the common enemy. Be merciful and show pity on him because it is possible that the devil through your wrath, will capture his soul and mortify it in resentment and thus, through your carelessness, the soul for whom Christ died is lost (1 Cor. 5:11).
St. John Climacus was asked if there are reliable signs by which it's possible to know whether a soul is drawing near to God or moving away from Him. After all, regarding ordinary things there are clear signs as to whether they're good or not. When, for instance, cabbage, meat or fish begins to rot, it's easy to notice it, since the rotting object begins to give off a foul odor, the color and taste change, and its external appearance witnesses to its deterioration. Well, and what about the soul? After all, it's bodiless and can't give off a bad smell or change its appearance. To this question the Holy Father replies, 'A sure sign of the deadening of the soul is the avoidance of church services.'
You have no peace from thoughts, which impel you to trouble others, and in turn to be troubled by others. But know, my brother, that if we offend by word or deed, we are thereby ourselves offended a hundredfold. Be longsuffering in all things and refrain from letting your own will enter into anything. Carefully examine your thoughts lest they infect your heart with deadly poison (ill temper) and make you take a gnat for a camel, a pebble for a cliff, and lest you become like a man who has a beam in his own eye but beholds the mote in the eye of another.