Deuteronomy 21:5

And the priests the sons of Levi shall come near. The presence of the priests at this ceremony was due to their position as the servants of Jehovah the King of Israel, on whom it devolved to see that all was done in any matter as his Law prescribed. The priests present were probably those from the nearest Levitical town. And by their word shall every controversy and every stroke he tried ; literally, And upon their mouth shall be every strife and every stroke , i . e . by their judgment the character of the act shall be determined, and as they decide so shall the matter stand (cf. Deuteronomy 10:8 ; Deuteronomy 17:8 ). In the present case the presence of the priests at the transaction gave it sanction as valid.