Honor your father and mother, so that your days will be lengthened upon the Land that Hashem, your G-d, Gives you. (Exodus 20:12)
To honor your father and mother is an honor to G-d. And in Biblical days, when Israel was a nation of G-d that followed His Laws, for children to honor their parents was to honor the Laws of G-d and follow in the ways of their parents--thus to be a nation of G-d that walks in the Ways of G-d. But if parents are not honorable, then how can they be honored? For if parents would rebel against G-d and teach corruption to their children, these parents should not be honored, but rather scorned and rebuked--and even punished. However, it is not the role of a child to judge his parents. And a child need not become a slave or a servant of his parents' household in order to honor his father and mother. To honor your parents is merely to honor their household, and thus honor your family, that you should not disgrace their name nor shame them, by speaking or acting against them.
When this is done--when people honor their parents--it is a blessing for the nation. Nations are built upon families, and families are built upon children and the honor of their household. When the family structure decays, nations decay. If children act irreverently towards their parents and people don't honor their father and mother, then why would anyone honor each other and why should people act Justly with one another? The family structure is the core of a society. If lawlessness prevails in the family, then lawlessness will prevail in the land. And if people would not even honor their parents, their own blood, then surely they would not honor G-d and would not keep His Laws.
Furthermore, parents care for their children as G-d Cares for His Creations and for His children. But just as G-d would destroy rebellious people and annihilate His wicked children, so would parents hate scornful children who turn against them. G-d Created people, and Breathed life into them, yet He Destroyed those who turned against Him; who followed the desires of their hearts and behaved wickedly--killing their fellow and destroying one another. If children would not honor their parents, then why should their parents want to care for them, and why should parents want to have children? If a nation is to survive and flourish, it needs children and it needs families. If Israel is to survive in its Land, its people must honor their father and mother. Therefore G-d Commanded us to "Honor your father and mother, so that your days will be lengthened upon the Land that Hashem, your G-d, Gives you."