Sanctify yourselves, by solemn purification and preparation of yourselves, both in soul and body. See Poole on "Exodus 19:10,15".
Related Commentaries of 1 Chronicles 15:12
1 Chronicles 15:12
12 And said unto them, Ye are the chief of the fathers of the Levites: sanctify yourselves, 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.