The Holy Prophet (S) said: "Verily, a servant can gain the rank of he who both fasts during the day and keeps vigil at night, keeping up prayers, through his good disposition."
Bihar-ul-Anwar, vol. 71, p. 373
Imam Amir ul Mu'mineen ‘Ali (‘a) told his son, Imam Hasan (‘a): "0' my son! No wealth is more valuable than intelligence and no poverty is similar to ignorance; no terror is worse than arrogance, and no life is more pleasant than being good tempered."
Bihar-ul-Anwar, vol. 78, p. 111
Imam Hasan ibn ‘Ali (‘a) said: "Verily, the best of bests is a good temper."
Khisal al-Saduq, p. 29
Imam Amir ul Mu'mineen ‘Ali (‘a) said: "Good behaviour lies in three traits: Avoiding unlawful things, acquiring the lawful ones, and being fair to one's family members."
Bihar-ul-Anwar, vol. 71, p. 394
Imam ‘Ali ibn Husayn, the fourth Imam, (‘a) said: "Fair speech increases wealth, stretches sustenance, postpones death, creates love among family members, and causes the person to enter Heaven."
Khisal by Saduq, p. 317
Imam as-Sadiq (‘a) said: "There are three things that each of which is brought by a person to Allah, He will necessitate Heaven for the one: donation in poverty, a good temper with all people, and justice to one's self."
Al-Kafi, vol. 2, p. 103
The Holy Prophet (S) said: "The things by which my Ummah can enjoy Heaven most of all are godliness, and a good temper."
Al-Kafi, vol. 2, p. 100