וירא יעקב מאד ויצר לו
Rashi explains that Yaakov was frightened that he would be killed, and he was distressed that, in his efforts to protect his family, he might kill acheirim, others. What did Yaakov fear? He had every reason to defend himself against Eisav. The Melei HaOmer explains that Yaakov purchased the firstborn birthright from Eisav for the express purpose that the avodah, service, in the Bais HaMikdash would be conducted by bechorim, firstborn, and he would be a b’chor. However, if he would kill Eisav – even by right – he could no longer serve. A Kohen that kills someone, even b’shogeig,…