رَبِّ ارْحَمْهُمَا كَمَا رَبَّيَانِي صَغِيرًا
Rabbir-hamhumaa kamaa rabbayaanii saghiira. (17:24)
My Lord, show them (my parents) mercy just as they cared for me when I was a little child.
This du’aa comes in the Qur’an immediately after the verse that tells us that deference to parents is the second most important obligation of a believer after the obligation to worship Allah Ta’aala alone. That placement in addition to the fact that Allah Ta’aala Himself is teaching us how to supplicate for our parents should tell us the value of this du’aa. That also raises our hopes regarding the acceptance of this du’aa when made sincerely.
Needless to say, it is an important parenting goal for Muslim parents to raise such children who will make this du’aa for them in their life and after their death.
(Source: Khalid Baig’s commentary to du’aa #17 in the Accepted Whispers: Munajat-e-Maqbul)