QUESTION: Is there a mitzvah to honor grandparents?
ANSWER: The Rema (Shulchan Aruch YD 240:24) brings two opinions as to whether there is a mitzvah to honor grandparents. The first opinion is that of the Maharik (shoresh 44) who writes that we do not find anywhere in the Talmud that there is an obligation to honor grandparents.
The Rema disagrees and writes that he believes there is an obligation, just that it is not as great as that of honoring parents. Rema offers proof from a Midrash (Bereishis Rabba 94:5). Yaakov Avinu offered korbanos to the G-d of his father Yitzchak—why not to the G-d of Avrohom? “R. Yochanan states that from here we see that one is obligated in the honor of his parents more than his grandparents.” The implication is that one must honor both one’s parents and grandparents, but the level of honor due to a parent is greater.
Most poskim, including the Shach and Taz, follow the ruling of the Rema. However, Sefer Elya Zuta (minhagim) and the Vilna Gaon support the opinion of the Maharik and offer the following proof. The Gemara (Sota 49a) relates that Rav Acha bar Yaakov raised his grandson who in turn also became a distinguished Amora. After he grew up, Rav Acha asked his grandson to get him a drink of water. He responded, “I am not your son.” From here it would seem that a grandson is not obligated at all in servicing his grandparents.
The Chasam Sofer (on Shulchan Aruch) negates this proof by suggesting that Rav Acha’s grandson was learning Torah at that time. He was obligated to honor his grandfather, but not at the expense of disrupting his learning. The Vilna Gaon distinguishes between maternal grandparents – for whom there is no obligation – and paternal grandparents – for whom there is. However, the Rema himself in a teshuvah (118) writes explicitly that there is no distinction, and one is obligated to honor both maternal and paternal grandparents.