None can deny the parents' favor upon their children. The parents are the underlying reason for the existence of the child. They have reared him in his babyhood and experienced painstaking efforts to provide full comfort and sound well-being. Your mother had you in her womb while you were a parasite there sharing her food and whole being for nine months. In this context, Allah says:
"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..." (31:14)

It is a preliminary stage followed by incubation and breast feeding for two years marked by peculiar fatigue and hardships. The father, on his part, is meanwhile also fully engaged catering for his child and bringing him up, not sparing any sort of instructions or guidance he could provide his child with; the child, meanwhile, a helpless creature is neither harmful nor useful to himself.

Allah has always enjoined that children should be good and thankful to their parents and He says:
"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." (31:14)

"... 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 honor. 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 small." (17:23, 24)

The right of parents upon you is to do good with them. You should be good to them physically as well as monetarily, and also with your words and your actions. You should be obedient to them unless in it there is disobedience to your Lord or there is some harm to you. Be kindhearted to them and serve them as they need your help. In their old age, in case of any ailment or weakness, never consider them a burden on you, neither speak to them harshly, because one day you will also become as old as they are. You will be a father as they are your parents and, if life permits, soon you will be an old man before your children just like your parents became old before you. So you need the help of your children as your parents need you today. If you are doing good to your parents then you must have the good news of a great reward and a better showing from your children, because whoever remained good to his parents, his children will also be good to him; and whoever annoyed his parents, will also be annoyed by his children. It is the process of recompense that deeds provide the results accordingly "as you sow, so will you reap. Allah has ranked the rights due to the parents high next only to His and the Prophet's, Allah says:
"Worship Allah and join none with Him in worship, and do good to parents..." (4:36)

And Allah also says:
"...give thanks to Me and to your parents... (31:14)

Being dutiful to one's parents assumes priority even over Jihad (fight in the cause of Allah) as is narrated in the tradition of Ibn Mas'ood  when he asked the Prophet (p.b.u.h.):
"Which deed is most beloved by Allah?" He said, 'Observing prayer in time.' "And next to that?" He said: 'Being dutiful to one's parents.' "And next to that?" He answered: 'Jihad (fight in the cause of Allah).'"

This Hadith (Prophetic saying) reported by Bukhari and Muslim points directly to the significance of the rights due to one's parents.

Unfortunately, most people have forgotten these rights, instead disobedience and severance of ties have risen to harden the hearts, and even they contempt and detest their parents. Some people have even deemed themselves superior to those two old good creatures. A recompense is sure in store for those disobedient children, sooner or later.