The Meaning of Restraining Anger
Kazm linguistically: kaf, za, and mim are a sound root that refer to a single meaning which is restraint and assemblage of a thing. It is said: kazamt al-qirbah if one fills up a bottle.  Maqayis al-Lughah, Ibn Faris (5/184); al-Kashf wa al-Bayan `an Tafsir al-Qur’an, al-Tha`labi (3/165); Lisan al-`Arab, Ibn Manzur (12/519).
Kazm technically: is restraining the self from absolution or anger.  al-Tawqif `ala Muhimmat al-Ta`arif, al-Manawi (p. 282).
Ghayz linguistically: is anger. It has also been described as the anger which comes about in the one incapable to act upon it. It is also said: it is more intense than anger. Furthermore, it is said that it is the violence and the first bouts of anger.  Jamharat al-Lughah, Ibn Durayd (2/932); al-Sihah, al-Jawhari (3/1176); al-Nihayah, Ibn al-Athir (3/402); Lisan al-`Arab, Ibn Manzur (7/450).
Ghayz technically: is the most intense form of anger. It is the heat that one finds from the blood boiling in his veins and heart. It is also said that it is the anger about one’s liver, and its force is the worst.  al-Tawqif `ala Muhimmat al-Ta`arif, al-Manawi (p. 282).
Kazm al-ghayz technically: is suppressing anger and swallowing it up, being patient over its cause. Also, it is described as not showing anger in word or deed despite having the ability to do so, causing it to befall upon one’s enemy.  Mu`jam Diwan al-Adab, al-Farabi (2/186); Tafsir al-Qurtubi (4/206); Fath al-Bari, Ibn Hajar (1/179). Encouragement towards Restraining Anger in the Qur’an and Sunnah
❖ Allah, exalted, says: “Hurry towards your Lord’s forgiveness and a Garden as wide as the heavens and earth prepared for the pious, who give, both in prosperity and adversity, who restrain their anger.” Al `Imran: 133 - 134.
❖ Sahl ibn Mu`adh ibn Anas al-Juhani narrates from his father, from the Prophet ﷺ: “Whoever restrains his anger whilst having the ability to realise it, Allah will call him forth above all creation to allow him to choose whichever houri he wishes.”  Reported by Abu Dawud (4777), al-Tirmithi (2021) and this is his wording, Ibn Majah (3394), and Ahmad (15637). al-Tirmidhi said: “It is sound, strange.” al-Mundhari mentioned in al-Targhib wa al-Tarhib (3/386) that the chain has `Abd al-Rahim ibn Maymun narrating from Sahl ibn Mu`adh. Ibn al-Mulaqqi weakened its chain in Sharh al-Bukhari (28/490). al-Albani authenticated in Sahih Sunan al-Tirmidhi (2021). Quotes of the Predecessors and Scholars on Restraining Anger
❖ `Ali, Allah be pleased with him, said: “Adhere to restraining your anger and your ends will be praiseworthy.”  Rawd al-Akhyar al-Muntakhab min Rabi` al-Abrar (p. 342).
❖ Ibn `Abd al-Barr said: “Whoever restrains his rage and repels his anger has humiliated his devil and his decency and religion are safe.”  al-Tamhid, Ibn `Abd al-Barr (7/250). Benefits of Restraining Anger
Its possessor is prepared for the Garden. Choosing among the houris. Overcoming Satan. Means to Acquiring Endearment
Recognising the reward that is subsequent to restraining one’s anger, pardoning the erroneous. Having mercy and compassion with the one who makes mistakes incites one to restrain one’s anger and put out its fire. Nurturing the self to be to be tolerant and expansive. Shyness from adopting the sins of the sinner and directly confronting him upon it. Desisting from excessive argumentation in hostile situation, not engaging in cursing and its like. Examples of Restraining Anger from the Biographies of the Prophet ﷺ, Companions, and Predecessors
❖ The Prophet ﷺ reached the epitome of forbearance and pardoning. The prophetic Sunnah is filled with examples of the Noble Messenger ﷺ exercising forbearance. Among those is the story of the bedouin who pulled the Prophet ﷺ from his clothing with a severe yank. Anas ibn Malik, Allah be pleased with him, narrates: “Once, I was walking with Allah’s Messenger ﷺ and he was wearing a cloak from Najran with a thick margin. A bedouin followed him and pulled his cloak so violently that I noticed the side of the shoulder of Allah’s Messenger ﷺ affected by the cloak’s margin because of that violent pull. The bedouin said: ‘Muhammad! Give me some of Allah’s wealth which is with you.’ Allah’s Messenger ﷺ turned and looked at him. He then laughed and ordered that he be given something.”  Reported by al-Bukhari (5809) and this is his wording, as well as Muslim (1057).
❖ Jubayr ibn `Abdillah said: “I witnessed Wahb ibn Munabbih, then a man came to him and said: ‘So-and-so was cursing you.’ He replied: ‘Did the devil find no one to belittle the intellect of other than you?’ I had only left Wahb briefly, then that man who had cursed him came. Wahb elevated his seat and ennobled him.’”  al-Wara`, Ahmad Riwayah al-Maruzi (p. 197). Proverbs, Adages, and Poetry about Restraining Anger
❖ “He is not befitting as a companion he who does not swallow his spittle.” It is a parable struck for the one who restrains his anger.
❖ al-`Arji said:
“If you anger, be poised and restraining
Of it, you’ll see what you say and hear it.
Suffice it as an honour, an hour’s patience -
Granting God’s pleasure and being elevated.”  al-Kashf wa al-Bayan, al-Tha`labi (3/166).