The fifth of the Ten Commandments expresses the imperative to honor one's parents. In the original Hebrew, the words are: Kabed et avicha v'et imecha. The Talmud derives from an extra letter in this verse, the vav in the word v'et, that one must also respect his elder brother.
Based on this, some say that respecting one's older brother is a Torah obligation. Others maintain that it is a rabbinic obligation, which merely finds support in the above verse.
Some say that this obligation only applies while one's parents are alive. Others say that it applies after they are deceased as well. Rabbi Ovadiah Yosef rules that one should be stringent in this matter.
Several reasons are given for this mitzvah:
- Parents educate their children to respect their elder siblings, it would therefore be disrespectful to the parents to disrespect one's elder sibling. The firstborn is also deserving of respect because he is considered somewhat responsible for his siblings. The Midrash explains that this is why Reuben saved Joseph from certain death at the hands of his brothers, suggesting instead that he be thrown into a pit (while intending to come back later to save him). For he said to himself, "I'm the firstborn; the blame [of Joseph's death] will fall only on me."
- According to Torah law, the firstborn son inherits more than his other siblings. This because the firstborn is considered his parents' representative—and as such deserves respect.
- The Arizal explains that the firstborn is a link in the chain that connects the souls of his younger siblings to his parents, and through them to G‑d. Therefore the siblings must respect him—just as they are obligated to respect their parents because they are the link that connects the person's soul to G‑d.
- The Birkei Yosef says that based on the understanding of the Arizal (cited above), one must also show respect to their older sister. In fact the Midrash says that Rachel was punished for talking before her older sister Leah. In addition, the Talmud says that the great sage Ulla would kiss his elder sisters' hands when they would leave the synagogue, as a sign of respect.
- Some say that the obligation only applies to one's oldest brother (who is firstborn). According to the Arizal, however, this mitzvah applies to all older siblings, as each one is the spiritual pipeline for the next sibling. Rabbi Ovadiah Yosef rules that one should show respect to all his elder siblings.
- The mitzvah applies to full or half siblings, whether paternal or maternal.
- This mitzvah applies even if the sibling is only a bit older. Even a younger twin must respect the older one.
- There is no obligation to show respect to an older sibling who is wicked.
- One should act and speak respectfully towards the older sibling.
- The mitzvah of "fearing" (one's parents) does not apply to older siblings. For this reason it is permissible for a younger sibling to call his older sibling by first name or to sit in his place (although one may not do these things towards a parent).