1 Chronicles 15:12

and said unto them, Ye are the chief of the fathers of the Levites, the leaders in these divisions of their tribes; sanctify yourselves, in the usual manner of setting themselves apart for a sacred duty, Exodus 19:10, both ye and your brethren, that ye may bring up the ark of the Lord God of Israel unto the place that I have prepared for it. He did not want his efforts to come to naught a second time on amount of non-observance of any prescribed forms.