Deuteronomy 21:5
And the priests the sons of Levi shall come near; for them the LORD thy God hath chosen to minister unto him, and to bless in the name of the LORD; and by their word shall every controversy and every stroke be tried: And the priests the sons of Levi shall come near; for them the LORD thy God hath chosen to minister unto him, and to bless in the name of the LORD; and by their word shall every controversy and every stroke be tried:
God set apart the priests of the tribe of Levi to come near to minister to Him. Their office was to serve Him directly and to pronounce blessing in His name. By their word every dispute and every case involving violence was to be tried and decided, giving their judgment final authority. In the ceremony for an unsolved murder their presence and judgment belonged to the public response to the crime. That requirement showed the killing must be met with solemnity, with its facts examined and its guilt faced rather than passed over or neglected.