Have you ever been welcomed to the “House of God” when you were sitting in a church building? Is this a correct use of the phrase “house of God”? Look at this passage:
Therefore, holy brothers, you who share in a heavenly calling, consider Jesus, the apostle and high priest of our confession, who was faithful to him who appointed him, just as Moses also was faithful in all God’s house. For Jesus has been counted worthy of more glory than Moses- as much more glory as the builder of a house has more honor than the house itself. (For every house is built by someone, but the builder of all things is God.) Now Moses was faithful in all God’s house as a servant, to testify to the things that were to be spoken later, but Christ is faithful over God’s house as a son. And we are his house if indeed we hold fast our confidence and our boasting in our hope. (Hebrews 3:1-6 ESV)
Notice that the author of Hebrews says that his readers are the “house of God”. Those who belong to God are his “house”, his dwelling place, over whom he, and he alone, is master. So, when you are sitting in a church building, you are not in the house of God; you are the house of God.