Is obedience to parents obligatory in a sin that does not amount to shirk with Allah?

It is not permissible to obey a creature in disobedience to the Creator, even if it is a father or mother, because the Prophet, peace and blessings be upon him, said: "Obedience is only in what is right," and "There is no obedience to a creature in disobedience to Allah, the Mighty and Majestic." This is what the scholars used to interpret the verse: "And We have enjoined upon man goodness to his parents. But if they endeavor to make you associate with Me that of which you have no knowledge, then do not obey them. To Me is your return, and I will inform you about what you used to do." [Al-Ankabut:8] And one must be gentle with them, even if their obedience in disobedience is not permissible.