"And We have enjoined on man (to be dutiful and good) to his parents. His mother bore him in weakness and hardship upon weakness and hardship, ... ..." (Surah Luqman, Chapter #31, Verse #14)

"And We have enjoined on man to be dutiful and kind to his parents. His mother bears him with hardship and ... ..." (Surah Al-Ahqaf, Chapter #46, Verse #15)

Narrated Abu Huraira: A man came to Allah's Apostle and said, "O Allah's Apostle! Who is more entitled to be treated with the best companionship by me?" The Prophet said, "Your mother." The man said. "Who is next?" The Prophet said, "Your mother." The man further said, "Who is next?" The Prophet said, "Your mother." The man asked for the fourth time, "Who is next?" The Prophet said, "Your father. " (Sahih Bukhari, Book #73, Hadith #2)

And (remember) when We took a covenant from the Children of Israel, (saying): Worship none but Allah (Alone) and be dutiful and good to parents, and to kindred, and to orphans and Al-Masakeen (the poor), (Tafsir At-Tabaree, Vol. 10, Page 158 (Verse 9:60)) and speak good to people (i.e. enjoin righteousness and forbid evil, and say the truth about Muhammad Peace be upon him ), and perform As-Salat (Iqamat-as-Salat), and give Zakat. Then you slid back, except a few of you, while you are backsliders. (Tafsir Al-Qurtubee, Vol. 2, Page 392). 
(Surah Al-Baqara, Chapter #2, Verse #83)

It is prescribed for you, when death approaches any of you, if he leaves wealth, that he make a bequest to parents and next of kin, according to reasonable manners. (This is) a duty upon Al-Muttaqoon (the pious - see V.2:2). 
(Surah Al-Baqara, Chapter #2, Verse #180)

They ask you (O Muhammad SAW) what they should spend. Say: Whatever you spend of good must be for parents and kindred and orphans and AlMasakin (the poor) and the wayfarers, and whatever you do of good deeds, truly, Allah knows it well. 
(Surah Al-Baqara, Chapter #2, Verse #215)

Worship Allah and join none with Him in worship, and do good to parents, kinsfolk, orphans, Al-Masakin (the poor), the neighbour who is near of kin, the neighbour who is a stranger, the companion by your side, the wayfarer (you meet), and those (slaves) whom your right hands possess. Verily, Allah does not like such as are proud and boastful; 
(Surah An-Nisa, Chapter #4, Verse #36)

Say (O Muhammad SAW): "Come, I will recite what your Lord has prohibited you from: Join not anything in worship with Him; be good and dutiful to your parents; kill not your children because of poverty - We provide sustenance for you and for them; come not near to Al-Fawahish (shameful sins, illegal sexual intercourse, etc.) whether committed openly or secretly, and kill not anyone whom Allah has forbidden, except for a just cause (according to Islamic law). This He has commanded you that you may understand. 
(Surah Al-Anaam, Chapter #6, Verse #151)

And your Lord has decreed that you worship none but Him. And that you be dutiful to your parents. If one of them or both of them attain old age in your life, say not to them a word of disrespect, nor shout at them but address them in terms of honour. 
(Surah Al-Isra, Chapter #17, Verse #23)

And We have enjoined on man to be good and dutiful to his parents, but if they strive to make you join with Me (in worship) anything (as a partner) of which you have no knowledge, then obey them not. Unto Me is your return, and I shall tell you what you used to do. 
(Surah Al-Ankaboot, Chapter #29, Verse #8)

And We have enjoined on man (to be dutiful and good) to his parents. His mother bore him in weakness and hardship upon weakness and hardship, and his weaning is in two years give thanks to Me and to your parents, unto Me is the final destination. 
(Surah Luqman, Chapter #31, Verse #14)

... many more in the Quran and Ahadith