Illustration Credit: Rivka Tsinman

This week’s parashah gives us the Torah’s first story of twins—two babies born to the same mother on the same day. This gives us a great chance to look at a halakhah-based riddle: How would it be possible for a younger twin to reach the age of mitzvot before her older sister? (Think about it for a minute before going on to see the answer!)

These twin sisters will become fully obligated in mitzvot at age 12. It would seem that the older one will certainly turn 12 years old before the younger one, right? But there is actually a wrinkle in the Jewish calendar that can complicate things!

First, let’s note that twins can be born hours and sometimes even days apart (even though it is rare). Let’s say that our twins are born during a Jewish leap year, when there are two months of Adar: אֲדָר רִאשׁוֹן (Adar Rishon, first Adar) and אֲדָר שֵׁנִי (Adar Sheni, second Adar). And let’s say the first twin is born at the very end of the 29th of Adar Rishon, and the second twin is born about 25 hours later, at the very beginning of the 1st of Adar Sheni.

Twelve years later, if it is not a Jewish leap year, then the first twin’s birthday will be marked on the 29th of Adar, but the second twin’s birthday will be on the 1st of Adar, 28 days earlier! Isn’t that weird? (See Shulhan Arukh Orah Hayyim 55:10.)

R. Yisrael Yaakov Hagiz in Responsa Halakhot Ketanot (II:174) suggests that maybe this is what happened with Esav and Yaakov! Maybe Esav was born first, but Yaakov thought he had a claim to the firstborn blessing because he reached the age of mitzvot first.

This is the sort of idea that takes details from our later calendar and projects them back onto the stories in the Torah. You have to admit it is an interesting way to think about the conflict between these two brothers!

-------------------

-------------------