“Your Lord has commanded that you worship none but Him, and that you be kind to your parents. If one or both of them reach old age with you, do not say to them a word of disrespect, or scold them, but say a generous word to them. And act humbly to them in mercy, and say, ‘My Lord, have mercy on them, since they cared for me when I was small” (17: 23-24).
The Prophet (peace and blessings be upon him) said, "He is not of us who does not have mercy on young children, nor honor the elderly" (Al-Tirmidhi).
Narrated Abu Musa al-Ash'ari: The Prophet said: Glorifying Allah involves showing honor to a grey-haired Muslim and to one who can expound the Quran, but not to one who acts extravagantly regarding it, or turns away from it, and showing honor to a just ruler (Sunan Abu Dawud).
Narrated Abu Bakrah: The Prophet said: There is no sin more fitted to have punishment meted out by Allah to its perpetrator in advance in this world along with what He stores up for him in the next world than oppression and severing ties of relationship. (Sunan Abu Dawud).
Narrated Abdullah ibn Amr ibn al-'As: The Prophet said: Those who do not show mercy to our young ones and do not realize the right of our elders are not from us (Sunan Abu Dawud).
The Prophet said: He does not belong to us who does not show mercy to our young ones and respect to our old ones, who does not recommend what is reputable and prohibit what is disreputable (Tirmidhi).
Narrated Abu Hurayrah: Allah's Apostle said: Let him be humbled into dust; let him be humbled into dust. It was said: Allah's Messenger, who is he? He said: He who sees either of his parents during their old age or he sees both of them, but he does not enter Paradise. (Sahih Muslim).
Narrated Abdullah ibn Umar: Allah's Apostle said: The finest act of goodness is the kind treatment of a person to the loved ones of his father after his death (Sahih Muslim).
Narrated Abdullah ibn Amr ibn al-'As: The Apostle of Allah said: Do not pluck out grey hair. If any believer grows a grey hair in Islam, he will have light on the Day of Resurrection. (This is Sufyan's version). Yahya's version says: Allah will record on his behalf a good deed for it, and will blot out a sin for it (Sunan Abu Dawud).
Photo Attribution: Amr Fayez - http://commons.wikimedia.org/wiki/File:Quran-Mus%27haf_Al_Tajweed.jpg