Mustadrak-ul-Wasa'il-ush-Shi'ah, vol. 15, p. 176
Imam 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 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 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-i-Kafi, vol. 2, p. 349
Imam 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."
AI-Kafi, vol. 5, p. 554
Imam 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