St. Tikhon of Zadonsk: Learn the sickness of Anger

 And see what anger can do in a man; how indignant and noisy he becomes, how he swears, how he beats his head, trembling as in a fever... Man, learn the sickness of thy soul, for without acknowledgment of illness there is no healing... Christ alone can heal us, who sigh and pray to Him with faith.

+St. Tikhon of Zadonsk, from Works, quoted in Saint Tikhon of Zadonsk, Inspirer of Dostoevsky, by Nadejda Gorodetzky

St. Dorotheos of Gaza: On remembering evil

 There are times when, with apparent sincerity, a man asks forgiveness of his brother after some discord between them or for some quarrel which has arisen, and yet after the reconciliation he still remains troubled and has hard thoughts against his brother. He ought not to dwell on such thoughts but to cut them off immediately, for this is remembering evil. It needs much self control not to prolong such thoughts and fall into danger.

+St. Dorotheos of Gaza, from Dorotheos of Gaza: Discourses and Sayings, chapter 8 On Rancor or Animosity.

St. John Cassian: Nothing is to be preferred to love

 Just as nothing is to be preferred to love, then, so also, on the other hand, nothing is to be less esteemed than rage and wrath. For everything, however beneficial and necessary it may appear, should nonetheless be put aside in order to avoid the disturbance of anger, and everything that may seem inimical should be put up with and tolerated in order to maintain unharmed the tranquility of love and peace, for it must be believed that nothing is more destructive than anger and annoyance and nothing more beneficial than love.

+St. John Cassian, from The Conferences, Conference 16; On Friendship #7

St. Seraphim of Sarov: On Spiritual Peace

 We can see how to defeat anger in the life of St. Paisius the Great. He asked the Lord Jesus Christ, Who appeared to him, to release him from anger. But Christ answered him, "If you want to defeat anger and wrath together, desire nothing, hate no one, humiliate no one."¹To preserve peace of soul you must keep despair at bay and try to preserve a joyful disposition, not a sorrowful one. As the wise Sirach said, "For sorrow has destroyed many, and there is no profit in it" (Sirach 30:23). To preserve peace of soul, you must in every way avoid condemnation of others. By you lack of judgment and your silence, you will preserve spiritual peace. When a man is in such a state, he receives divine revelations.

+St. Seraphim of Sarov, from Spiritual Instructions, #3-4 On the Peace of the Soul and Preserving It.

¹ from the Life of St. Paisius the Great in The Great Synaxaristes, June 19

Evagrius Ponticus: On the Right and Wrong use of Anger

 Anger is given to us so that we might fight against the demons and strive against every pleasure. Now it happens that the angels suggest spiritual pleasure to us and the beatitude that is consequent upon it so as to encourage us to turn our anger against the demons. But these, for their part, draw our anger to worldly desires and constrain us - contrary to our nature - to fight against our fellow men to the end that, blinded in mind and falling away from knowledge, our spirit should become a traitor to virtue.

+Evagrius Ponticus, from The Praktikos, #24

Fr. Alexander Elchaninov: A false spirituality

 There is a type of spirituality closely enmeshed with the emotions - aesthetic, sentimental, passionate - which can easily coexist with selfishness, vanity, and sensuality. Men of this type seek the praise and good opinion of their spiritual father; it is a very hard task for him to hear and accept their confession, for they come in order to complain of others, to whimper; they are full of themselves and readily accuse their neighbor. The poor quality of their religious devotion is best demonstrated by the ease with which they pass into a state of anger and irritation. They are further from the possibility of genuine contrition than the most inveterate sinners.

+Fr. Alexander Elchaninov, from The Diary of a Russian Priest, Fragments of a Diary

St. John Cassian: Struggle against the demon of anger

Our fourth struggle is against the demon of anger. We must, with God's help, eradicate his deadly poison from the depths of our souls. So long as he dwells in our hearts and blinds the eyes of the heart with his somber disorders, we can neither discriminate what is for our good, nor achieve spiritual knowledge, nor fulfill our good intentions, nor participate in true life; and our intellect will remain impervious to the contemplation of the true, divine light; for it is written, "For my eye is troubled because of anger" (Ps 6:7 LXX). Nor will we share in divine wisdom even though we are deemed wise by all men, for it is written: "Anger lodges in the bosom of fools" (Exxles 7:9). Nor can we discriminate in decisions affecting our salvation, even though  we are thought by our fellow men to have good sense, for it is written: "Anger destroys even men of good sense" (Prov 15:1 LXX). Nor will we be able to keep our lives in righteousness with a watchful heart, for it is written: "Man's anger does not bring about the righteousness of God" (James 1:20). Nor will we be able to acquire the decorum and dignity praised by all, for it is written: "An angry man is not dignified" (Prov 11:25 LXX).
If, therefore, you desire to attain perfection and rightly to pursue the spiritual way, you should make yourself a stranger to all sinful anger and wrath. Listen to what St. Paul enjoins: "Rid yourselves of all bitterness, wrath, anger, clamor, evil speaking and all malice" (Eph 4:31). In saying 'all' he leaves no excuse for regarding any anger as necessary or reasonable. If you want to correct your brother when he is doing wrong or to punish him, you must try to keep yourself calm; otherwise you yourself may catch the sickness you are seeking to cure and you may find that the words of the Gospel now apply to you: "Physician heal yourself" (Luke 4:23), or "Why do you look at the speck of dust in your brother's eye, and not notice the rafter in your own eye?"(Matt 7:3).
+St. John Cassian, from On the Eight Vices, #4 On Anger, in The Philokalia, V 1.