One of the best deeds that a person can do, in fact, the most important and greatest act of worship after worshipping Allah, is being dutiful to your parents. The rights of the parents are indeed very great, and it is because of this that if a person fulfils these rights, they earn a high status with Allah. Of the blessings that such a person receives is that their du’a is answered.
This is illustrated in the hadith of Uways al-Qarni, who among the tabien had the highest status of all. ‘Umar ibn al-Khattab, may Allah be pleased with him, narrated that he heard the Prophet, peace and blessings of Allah be upon him, say:
“There will come to you (a man by the name of) Uways ibn Amir, with some people from yemen. He is from (the tribe of) Murad, then from Qarn. He was afflicted with leprosy (all over his body) except for one part, the size of a dirham. He has a mother to whom he is very dutiful. If he were to swear by Allah, Allah would fulfill his oath. If you are able to ask him to seek your forgiveness, the do so.” (Recorded in Muslim)
When ‘Umar heard this, he waited until Uways came to Madinah, and then asked him to make du’a for him.
This hadith shows us that being dutiful to our parents is a cause of our du’a being accepted, because the reason that Uways’s oath was responded to was because of the devotion that he displayed towards his mother.