He that kills a person accidentally... shall
remain [exiled in the "city of refuge"] until the death of the High
Priest (Numbers 35:11, 25)
The mothers of high priests would provide food and clothing for the
exiled killers, that they should not pray for their son's death.
Why is the High Priest to blame? --As they say here [in Babylon], "Toby
did the jobbing and Ziggad got the slogging?" or as they say there [in the
Land of Israel]: "Shechem got him a wife and Mabgai caught the knife?"
Said a venerable old scholar: I heard an explanation at one of the seasonal
lectures of Raba, that he failed to prayed for his generation.
As was the case of that fellow who was devoured by a lion some three
parasangs from Rabbi Joshua ben Levi's town, and Elijah the
Prophet refused to visit Rabbi Joshua on that account for three days.
(Talmud, Makot 11a)