Shabbat Vayehi 5778

When Yosef presents his two sons, Menashe and Ephraim, to their grandfather to receive a blessing, Ya’akov does something that disturbs the apparent natural order of things: “But Israel stretched out his right hand and laid it on Ephraim’s head, though he was the younger, and his left hand on Menashe’s–thus crossing his hands–although Menashe was the first-born” (Genesis 48:14)
Setting aside the question of why the Torah yet again champions the younger son over the older, let’s explore a different question. Why does the right hand have to go on the child receiving the primary blessing? What is it about righthandedness that is made such a priority in a religious society?
Rabbi Ethan Tucker of Mechon Hadar has written extensively on this question, and sees it as an expression of one of the key questions of community-building and boundary-setting: the matter of negotiating uniformity and diversity. As we prepare to look at this together on Shabbat morning, here are a few halakhic trivia questions for you:
1. Was a left-handed kohen permitted to participate in Temple services?
2. What hand do lefties use to hold the lulav and etrog?
3. If a lefty writes on Shabbat while using his/her right hand, is s/he liable for having violated Shabbat?
4. What if a right-handed person wants to wear tefillin on her/his right arm? 
Finally, why does any of this matter? We’ll have fun with these questions on Shabbat morning.
Wishing you a Shabbat Shalom,
Rabbi David Wise