The reason behind the commandment to honor parents is understandable at the intellectual level, since they bring us into the world and raise us, go hungry to feed us, go naked to clothe us and meet all our needs until we mature. It is therefore appropriate not to be ungrateful, there being no worse attribute. Our sages, of blessed memory, said that a person has three partners, and equated the honor and reverence due to them with those pertaining to the Holy one, blessed be He. The importance of this obligation is established in the Ten Commandments. It comes with a reward, since it says "so that you may fare well and have a long life".