The Gemara says that if one's parents are divorced and both the father and mother ask for water - he can give either one first. The obligation to honor them is EQUAL.
What is the din if the father tells the son NOT to bring the mother the water - may the son listen? Maybe it is a case of the father telling the son not to do a mitzva. Or maybe it is a case of telling the son to do a mitzva i.e. listening to the father?!!!
