What does it mean for the LORD to build his house?
1 Samuel 2:35 (ESV)
35And I will raise up for myself a faithful priest, who shall do according to what is in my heart and in my mind. And I will build him a sure house, and he shall go in and out before my anointed forever.
The Lord building his house has to do with the lineage and descendants of the faithful priest. He and his descendants will be the ones to fill the office of high priest in Israel.
35 And I will raise up for myself a faithful priest, who shall do according to what is in my heart and in my mind. And I will build him a sure house, and he shall go in and out before my anointed forever.