When Not To Obey - An Exception

There is but one important qualification.

The fact that the precepts to honor and revere parents are commands of G-d implies not only the wide extent and significance of these Mitzvos, but also their limitation. It is G-d Who prescribes these Mitzvos, and it is G-d's Torah which delineates their specific details.

These Mitzvos are, therefore, integral parts of Torah and subject thereto. They can never apply to incidents that would contravene the letter or spirit of the Torah:

"'Ye shall fear every man his mother and his father, and ye shall keep my Sabbaths; I am the L-rd your G-d.' Scripture juxtaposes the observance of the Sabbath to the fear of one's father in order to teach you that 'although I admonish you regarding the fear of your father, yet if he bids you to desecrate the Sabbath do not listen to him [and the same is the case with any of the other commandments], for 'I am the L-rd your G-d' - both you and your father are equally bound in duty to honor Me. Do not, therefore, obey him if it results in disobeying My words.'" [Rashi on Lev. 19:3; Yevamos 5b; Bava Metzia 32a.].

If parents would order their child to transgress a positive or a negative command set forth in the Torah, or even a command which is of rabbinic origin, the child must disregard the order. Moreover, in the event that the father requests a personal service from his son while the son has a Mitzvah to perform, then: if the Mitzvah can be performed by others, let him delegate it to others and attend to the duty of honoring his father, for one commandment is not to be neglected in order to fulfill another. But if there are no others to perform the Mitzvah (and it cannot be postponed), he must perform it himself and disregard the honor due his father, because both he and his father are duty bound to fulfill the commandment. The latter would include especially the duty of studying Torah which supersedes that of honoring parents [Hilchos Mamrim 6:12f., Shulchan Aruch, ibid, 240:12f and 25 (note the commentaries ad loc.).].