Sefer Ha’mitzvos Ha’Katzar (The concise book of mitzvos)
By the Chofetz Chaim
This book lists the Torah mitzvos that can be observed today
First Section – the Positive Commandments
41. It is a positive commandment to honor one's father and mother
As it states in Shemos (Exodus) 20:12, "Honor your father and your mother." What is honor? Feed them, give them to drink, and cloth them, with the father's money. If the father has no money and the son does have money, the son is compelled to take care of his father with his own funds. A child should honor his parents like a servant to a master. He should honor them after they have passed away.
If his father says to him, 'Get me water,' and in front of him is another commandment to do, if the commandment in front of him can be done by someone else, he should honor his father. If the commandment cannot be done by someone else, he should do the commandment. Of course, if his father told him to do a sin, even on a Rabbinic commandment, he should not listen to him, because both are required to honor G-d.
Honoring one's father comes before one's mother, because the mother is required to honor his father also. One that is lenient in honoring his father and mother, has transgressed a positive commandment, unless it was done with their knowledge and consent. A women is also required in this commandment, but if her husband prevents her from doing it, then she is exempt.
This commandment applies in all places and at all times.