"Then they went into Capernaum, and immediately on the Sabbath He entered the synagogue and taught. And they were astonished at His teaching, for He taught them as one having authority, and not as the scribes. Now there was a man in their synagogue with an unclean spirit. And he cried out, saying, “Let us alone! What have we to do with You, Jesus of Nazareth? Did You come to destroy us? I know who You are—the Holy One of God!”
But Jesus rebuked him, saying, “Be quiet, and come out of him!” And when the unclean spirit had convulsed him and cried out with a loud voice, he came out of him. Then they were all amazed, so that they questioned among themselves, saying, “What is this? What new doctrine is this? For with authority He commands even the unclean spirits, and they obey Him.” And immediately His fame spread throughout all the region around Galilee."
The fact that there was a man sitting in the midst of the synagogue with an unclean spirit, (while Jesus taught!) tells us that satan and evil spirits don't care about a physical building at all, they are not bound by the physical. And it doesn't matter how historical or the name of the building, demons can and will enter a building with the label "church" on it and feel quite comfortable IF there is no one in that building with the Holy Spirit and anointing of God IN their souls.
If there is no one with the power and authority of Jesus to cast out the devils that inhabit the bodies of the wicked and believers as well, inside buildings and outside, then the demons will be free to do what they will.
What those who are truly in Christ must understand is that WE ARE THE CHURCH! And if the Spirit of God dwells in you, then it doesn't matter where you step your foot, God is with you in that place!
1st Corinthians 3:16
"Do you not know that you are the temple of God and that the Spirit of God dwells in you?"
Did Paul tell the Corinthian saints that the physical temple of Jerusalem at that time was the temple of God? NO! He told them that THEY were the temple of God!
Jesus knew that His body was a temple of God.
"Jesus answered and said to them, “Destroy this temple, and in three days I will raise it up.” Then the Jews said, “It has taken forty-six years to build this temple, and will You raise it up in three days?” But He was speaking of the temple of His body."
Paul quoted the prophets and reiterated to the Corinthians what God Himself said.
2nd Corinthians 6:16
"For you are the temple of the living God. As God has said: “I will dwell in them And walk among them. I will be their God, And they shall be My people.”
Eventually the demons will manifest (show themselves) in the presence of one with the power, authority, and grace of God emanating from their spirits. Even Judas who was with Jesus His whole ministry, eventually showed himself for who he was, a betrayer and a devil!
No, the church is not a building and never will be. And when the buildings that are called 'the church' are no more, then those in whom God dwells will stand strong in His power and His might!
"And I also say to you that you are Peter, and on this rock I will build My church, and the gates of Hades shall not prevail against it."