The Torah commands in the beginning of Parashat Kedoshim (19:3), “Ish Imo Ve’abiv Tira’u” – that one must show reverence for his father and his mother. The Gemara explains that “reverence” in this context means that one may not sit in his parent’s place, speak in a parent’s place when the parent in speaking to other people, or contradict a parent’s words. The Sefer Ha’hinuch writes that even if a parent acted improperly by striking or spitting at the child, the child should not disgrace the parent. It must be noted, however, that it is forbidden for a parent to strike his or her grown child, as this will likely cause the child to become very angry and strike the parent in response. By striking the child, the parent is thus in violation of the prohibition of “Lifneh Iver,” which forbids causing another person to sin. The Sefer Ha’hinuch writes that even if the parent’s mental faculties become compromised, and the parent acts insensibly, the child must continue treating the parent with respect. If the parent loses his or her sanity altogether, the child is permitted to put the parent under the care of someone who is capable of treating and caring for the parent. A Mamzer – the product of an incestuous or adulterous relationship – is obligated to show respect and reverence to his parents. Although he obviously has a legitimate grievance against his parents, for producing him through an illicit relationship which resulted in his status as a Mamzer, nevertheless, he is bound by the obligation to show his parents respect and reverence. However, a Mamzer is not liable to capital punishment for striking or cursing a parent, as others are. If a parent instructs a child to violate Torah law, or even to violate a law enacted by the Sages, the child must respectfully disobey. The Rambam, surprisingly, ruled that just as one may not address his parent by name, he may not even address by name someone who shares the parent’s name. Even if the parent is not present, the Rambam maintained, one is not permitted to call someone by name if that person has the same name as his or her parent. The Gaon of Vilna (Rav Eliyahu of Vilna, 1720-1797) suggested that the Rambam’s view is sourced in the story of the famous Talmudic sage Abayeh, who was orphaned at a young age. He was raised by Rabba, who gave him the name “Abayeh,” the Aramaic word for “father.” Rather than give him his deceased father’s name – Nahmani – Rabba decided to name him “Abayeh.” The reason, the Gaon of Vilna suggested, is because Rabba’s father was also named Nahmani, and thus Rabba was not able to call another person by this name. Of course, common practice does not follow this opinion, and in fact, among Sefaradim, it is customary to specifically give one’s child the grandparent’s name even during the grandparent’s life. This Misva applies in all times and in all places, and to both men and women. One who fails to treat his or her parent with the required reverence transgresses an affirmative command, unless the parent waives his or her right to reverence, as Halacha absolves a child of this obligation if the parent waives this requirement.