The final cure for this sickness is to realize that we must not become angry for any reason whatsoever, whether just or unjust. When the demon of anger has darkened our mind, we are left neither with the light of discrimination, nor the assurance of true judgment, nor the guidance of righteousness, and our soul cannot become the temple of the Holy Spirit. Finally, we should always bear in mind our own ignorance of the time of our death, keeping ourselves from anger and recognizing that neither self-restraint nor the renunciation of all material things, nor fasting and vigils, are of any benefit if we are found guilty at the last judgment because we are the slaves of anger and hatred.
~St John Cassian
You cannot be too gentle, too kind. Shun even to appear harsh in your treatment of each other. Joy, radiant joy, streams from the face of him who gives and kindles joy in the heart of him who receives. All condemnation is from the devil. Never condemn each other. We condemn others only because we shun knowing ourselves. When we gaze at our own failings, we see such a swamp that nothing in another can equal it. That is why we turn away, and make much of the faults of others. Instead of condemning others, strive to reach inner peace. Keep silent, refrain from judgment. This will raise you above the deadly arrows of slander, insult and outrage and will shield your glowing hearts against all evil.
~ St Seraphim of Sarov via Mind in the Heart
In all your affairs rely wholly on divine Providence, through which alone you must look for success; labor, nevertheless, quietly on your part to cooperate with its designs, and then you may be assured, if you trust as you ought in God; the success which shall come to you shall be always that which is the most profitable for you, whether it appear good or bad according to your private judgment. Imitate little children who, as they with one hand hold fast by their father, and with the other gather strawberries or blackberries along the hedges; so you, gathering and handling the goods of this world with one hand, must with the other always hold fast the hand of your heavenly Father, turning yourself towards him from time to time to see if your actions or occupations be pleasing to him; but above all things take heed that you never leave his protecting hand nor think to gather more, for should he forsake you, you will not be able to go a step further without falling to the ground.
~Saint Francis de Sales, Introduction to the Devout Life