The central elements in the Old Covenant were sacrifice, priesthood, and tabernacle. The New Testament Scriptures, especially the letter to the Hebrews, teach us that Christ Jesus was the fulfillment of sacrifice, priesthood, and tabernacle. Jesus is our high priest; therefore we have no need for earthly priests (Heb. 4:14; 8:1). In fact, the priesthood has been expanded to include all believers (1 Pet. 2:5, 9; Rev. 1:6)—men, women, and children. Jesus is the true and perfect sacrifice, offered once for all, so that no further sacrifice is either necessary or possible (Heb. 7:27; 9:14, 25-28; 1 Pet. 3:18). Jesus is also the fulfillment of the tabernacle (Heb. 8-9; see 9:24). The need for an earthly tabernacle has passed away (John 4:20-24). "The Word became flesh and tabernacled among us" (John 1:14; cf. 1:17). Jesus identified His body with the temple (John 2:19-21). He is Emmanuel, God with us (Matt. 1:23).
Sacrifice, priesthood, and tabernacle were all instituted through Moses. Theologically, all passed away with the coming of Jesus and the birth of the Ekklesia (Assembly, Congregation). Historically, all three passed away with the destruction of Jerusalem in A.D. 70. They had become irrelevant, anachronistic. The New Covenant has no need of sacrifice, priesthood, and tabernacle, because the Ekklesia together with Jesus are all three. Our lives are to be a "living sacrifice" (Rom. 21:1). We are the temple of God (Heb. 9:11). Every believer is a priest, having no need of any so-called "spiritual authority" other than Christ Jesus Himself (1 Pet. 2:5, 9; Rev. 1:6). The only missing piece was a place to meet, and the most logical place to meet was the home (Acts 2:46; 5:42). Theologically, the Ekklesia does not need temples! Church buildings are not essential to the true nature of the Ekklesia.
The great temptation of the organized church has been to reinstate all three of these elements among Yahweh God's people: to turn community into an institution, set up a professional priesthood, turn the Lord's Supper into a new sacrificial system, and build great cathedrals. None of this is to be found in the New Testament Scriptures. This is all taken from the Old Testament Scriptures. It is a mixing of oil and water; a mixing of new wine with old wineskins, Law or legalism with grace.
Church buildings are a return to the shadow of the Old Testament, a betrayal of the reality of the New Testament. Theologically, church buildings are at best unnecessary and at worst idolatrous.