There are several verses in the Qur'an that enjoin on Muslims the duty of being kind and compassionate to their parents. In almost every case, this injunction appears soon after the injunction to worship only one God. This shows how important it is in Islam to treat parents properly.
In the Qur'an, Allah asks Muslims to show kindness to their parents and forbids them from making even the smallest gesture or uttering even the smallest word of reproach to them. No impatience, disrespect, or contempt may be shown to parents.