Numbers 9:8

And Moses said unto them, stand still
Where they were; Aben Ezra says, at the door of the tabernacle of the congregation:

and I will hear what the Lord will command concerning you;
as it was a singular case, of which there had been no instance before, Moses would not determine anything about it himself, but would inquire of the Lord his mind and will concerning it; and for that purpose, very probably, went into the most holy place, where the Lord had promised to meet him and commune with him, from off the mercy seat, about any matter of difficulty he should inquire about, ( Exodus 25:22 ) .