It used to be that if a person murdered accidentally, he would go to a city of refuge and stay there until the death of the Cohain Gadol (high priest). Therefore, in Tractate Makkos, we learn the mothers of the Cohain Gadol would bribe the murderers (who are partially liable, if it was completely accidental and out of their hands, then there is no punishment. These people were partially at fault for the murder) so they would not pray for their son’s death. The question is obvious: why were the mothers so worried about these prayers? These people were murderers – do we really think their prayers will be answered. The reason is because the accidental murderers realize there’s only one way they’ll get out of the city of refuge, and that is from G-d. They pray to G-d with everything they have and have perfect faith in Him. When a person has perfect faith in G-d, then G-d answers them.