The Holy Prophet (S) said: "The pleasure of Allah lies in the pleasure of one's parents (in the case that it is right), and His wrath lies in their wrath."
Mustadrak-ul-Wasa'il-ush-Shi'ah, vol. 15, p. 176
Imam as-Sadiq (‘a) said: "The best deeds are: punctual prayer, kindness to parents, and contributing to the Holy War (against the pagans) in the path of Allah."
Bihar-ul-Anwar, vol. 74, p. 85
Imam as-Sadiq (‘a) said: "He who wishes Allah, Almighty and Glorious, to lighten the agonies of death, he should have regard for his kinship, and treat his parents with goodness. Then, when a person does so, Allah will make the agonies of death easy for him and he will not be stricken by poverty in his life at all."
Safinat-ul-Bihar, vol. 2, p. 553
Imam as-Sadiq (‘a) said: "He who glares at his parents with wrathful eyes, although they have been unjust to him, Allah will not accept his prayers (unless he repents)."
Usul al-Kafi, vol. 2, p. 349
Imam as-Sadiq (‘a) said: "Do treat kindly your parents so that your children do the same to you; and be pious unto the wives of people so that your wives remain pious."
Al-Kafi, vol. 5, p. 554
Imam as-Sadiq (‘a) said: "Once a person came to the Prophet (S) and asked him about good treatment to parents. Then, he (S) said 'Treat kindly your mother, treat kindly your mother, and treat kindly your mother; be kind to your father, be kind to your father, and be kind to your father but begin (that kindness) with your mother before your father'."
Al-Kafi, vol. 2, p. 162