This week we begin worship with:
We are the temple of the living God; as God said, “I will make my dwelling among them and walk among them, and I will be their God, and they shall be my people.
The word for temple (naos) is specifically the sanctuary itself (The Holy Place and the Holy of Holies). This is the portion of the temple where the Glory of the Lord dwelt and where the priests operated. It is not the outer courts where lay people were permitted to worship.
But this verse upsets that order. Paul, using multiple verses from the Old Testament, declares that we are instead that sanctuary and are indwelled by the Living God.
What is the difference between something sacred and something profane (For example, a church and any other building)? It is not the type of masonry, paint, or the color of the carpet. It is that it has been set aside for God's use.
This verse then reminds us that because we are God's dwelling we are to be set aside exclusively for His use.
One can hear that exclusivity in the word "my". We are to be no other's.