The unintentional murderer is different from and similar to other unintentional sinners of serious crimes. Other offenders bring a sacrifice. The unintentional murderer, in effect, sacrifices his freedom to obtain atonement for his mistake. The murderer stays in an ir miklat (city of refuge) until the death of the Kohen Gadol (High Priest). A few interesting explanations are given for the Kohen Gadol’s place in this context.
Rashi’s first explanation is that the murderer is not worthy to be free and encounter the Kohen Gadol, for the latter extends man’s life through his holy activities, while the former shortened someone’s life. The Seforno says that having a deadline for release from ir miklat is important in that it enables Divine Providence to distinguish between those who need a longer or a shorter term in ir miklat. Thus, if an unintentional murder was more grievous, it is more likely to have taken place when the Kohen Gadol had longer to live, thus extending his term. Rashi’s second explanation is that the Kohen Gadol should be in a position that people will await his death, for it was his shortcoming by not praying sufficiently well that allowed bloodshed to occur. We see, then, that spiritual leaders have much accountability for their "flock’s" shortcomings.
The Aramaic translation/commentary of Yonatan ben Uziel says something similar to Rashi’s second idea, but with an important twist. He says that it is fitting for the Kohen Gadol to die for not properly praying on Yom Kippur, inside the Holy of Holies, that Bnei Yisrael should not stumble in the three cardinal sins of bloodshed, adultery and incest, and idolatry. Rashi puts responsibility on the Kohen Gadol regarding the tragedy of the death. In contrast, Yonatan ben Uziel focuses on the Kohen Gadol’s responsibility regarding the tragedy of the sin. It is unclear if the idolatry and sexual sins that he refers to are purposeful violations or whether one did not realize that his action was forbidden. However, either way, it does not seem comparable to someone who did not even plan to strike anyone but to chop down a tree. While the tragedy is clear by an unintentional murderer, the sin is not.
The shortcoming of the unintentional murderer is not retroactive, when someone is killed, but begins before. There are various commandments to take steps to preserve our counterpart’s life. One who is not careful is one who violates the imperative not to be reckless. The responsibility of the Kohen Gadol is two-fold, to teach people not to be potential murderers and to pray that the potential should never be realized. That is the case by idolatry and sexual crimes as well. One exposes himself to moral dangers by his actions without necessarily planning to step over the line of a full-fledged, cardinal transgression. Before one knows it, he can fall into the trap of sin. Let us be careful enough to avoid a variety of possible tragedies.