In the Holy Qur'an

And we have enjoined man in respect of his parents (31:14)

And that ye be kind to your parents, Say not to them (so much as) ‘Fie’ nor chide them, but speak to them a generous word. (17:23)

In the Traditions

O God,

Fill me with awe of my parents,
and the awe one has towards a tyrannical sovereign,
and let me be devoted to them,
with the devotion of a compassionate mother!

Make my obedience and devotion to them
more gladdening to my eyes
than sleep to the drowsy
and more refreshing to my breast
then drink to the thirsty,
so that I may prefer their inclination
to my inclination,
set their satisfaction
before my satisfaction,
make much of their devotion to me
though it be little,
and make little of my devotion to them
though it be great.

Excerpt of Supplication for his Parents by Imam Zain Al Abideen