John Gill Commentary 1 Chronicles 15:3

"And David assembled all Israel at Jerusalem, to bring up the ark of Jehovah unto its place, which he had prepared for it." — 1 Chronicles 15:3 (ASV)

And David gathered all Israel together to Jerusalem
The chief and heads of the people:

to bring up the ark of the Lord ;
from the house of Obededom, where it had been three months, and for the sake of which his house was blessed, and which David heard of; and this encouraged him to take this step to fetch it from thence: unto his place, which he had prepared for it; (1 Chronicles 15:1) (2 Samuel 6:12 2 Samuel 6:17) .