Importance of Honouring Parents in Islam
Question

What is the importance of honouring parents in the light of the Quran and Sunnah?
Praise be to Allah.Importance of honouring parents in Islam

Honouring parents in Islam is obedience to Allah and His Messenger (peace and blessings of Allah be upon him). Allah says (interpretation of the meaning):

“And We have enjoined on man to be good and dutiful to his parents?” [al-Ankabut 29:8]
“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. And lower unto them the wing of submission and humility through mercy, and say: My Lord! Bestow on them Your Mercy as they did bring me up when I was young.” [al-Isra 17:23]
In al-Sahihayn, Ibn ‘Abbas said: The Messenger of Allah (peace and blessings of Allah be upon him) was asked which deed is the best? He said: “ Faith in Allah and His Messenger, then honouring one's parents.” There are many other verses and Mutawatir hadiths which say similar things.

Obeying and honouring one's parents is a means of entering Paradise, as it was reported in Sahih Muslim from Abu Hurayrah that the Prophet (peace and blessings of Allah be upon him) said: “He is doomed, he is doomed, he is doomed. It was said, Who, O Messenger of Allah? He said, “The person whose parents, one or both of them, reach old age during his lifetime but he does not enter Paradise.”  (Sahih Muslim, 4627).
Respecting and honouring parents brings friendship and love.
Respecting and obeying parents is a way of showing gratitude to them because they are the ones who brought you into this world. You should also show gratitude towards them for bringing you up and taking care of you when you were young. Allah says (interpretation of the meaning):

“And We have enjoined on man (to be dutiful and good) to his parents.” [Luqman 31:14]

If a person honours his parents, this may be the cause of his own children honouring him. Allah says (interpretation of the meaning):

“Is there any reward for good other than good?” [al-Rahman 55:60]
And Allah knows best.