Bemidbar 35:28 (Mase'ei) - Something unpredictable

Bemidbar 35:28 records that if a person kills accidently, then he must remain in the city of refuge until the high priest dies. What is the connection between the death of the high priest and the permission for the accidental killer to leave the city of refuge?

Rambam (Moreh 3:40) explains that the death of the high priest will abate the desire of the relatives of the victim for revenge. This idea follows the approach that the city of refuge was an asylum.

A popular approach (see Rashi and Luzzatto on 35:25) is that the death of the high priest serves as a form of atonement for the accidental murderer. Just as the actions of the high priest, as for example on Yom Kippur, bring atonement to people, so too his death brings atonement for the accidental murderer. This approach follows the idea that the city of refuge was for the accidental murderer to attain atonement.

Seforno suggests that as the responsibility for the accidental murder differs in each case due to the "degree of accident" involved in the particular case, so then the stay in the city of refuge also differs. This leaves the judgment to G-d to ensure that those accidental murderers who are relatively guiltier will stay in the city of refuge for longer time periods. This approach follows the idea that the city of refuge is to punish the accidental murderer.

My guess is that the conditioning of the release of the accidental killer from the city of refuge upon the death of the high priest is to make the accidental killer's stay in the city of refuge indeterminate since who knows how long the high priest will live. This indeterminacy matches the accidental nature of the murder since both are unpredictable. The "punishment" for killing accidentally then follows the usual formula of being a measure for measure. With this idea, the death of the high priest is ad hoc. There is a need for some unpredictable event to end the period of asylum, and the death of the high priest serves this purpose. As discussed in our commentary on Shemot 2:11-23 "An accident," (http://www.lobashamayim.blogspot.co.il/2010/01/shemot-216-23-shemot-moshes-flight.htmlI believe that the death of Pharaoh served the same purpose to enable Moshe to return to Egypt.