The Bible tells us that God chose Jerusalem as the place to put His name and build up His habitation. God told His people that when they got into the good land, they had no right to choose the place in which they would worship Him. They had to go to the place of His choice. He would choose a place out of all their tribes to put His name and to build up His habitation (Deut. 12:5). They all had to come to that unique place to worship the Lord. This was for the keeping of the unity. It was by this unique place of worship to God that the unity of His people was kept for generations. This unique place was Jerusalem. In Jerusalem the house of God was built, and the glory of God filled that house (1 Kings 8:10-11). That was the golden age of the history of the people of Israel.
Later, King Nebuchadnezzar of Babylon came to destroy Jerusalem. He burned the house of God in Jerusalem, carried away all the vessels in God's house for God's worship, and put them in the temple of his idols in Babylon (2 Chron. 36:6-7). What a contradiction this was. This shows that even in Babylon, there are some of the things related to God. In the temple of idols in Babylon, there are some vessels belonging to God's house. This brings us to the fourth point concerning Babylon: it is a mixture of the things of God with the things of the idols. The vessels used in God's house were in the temple of the idols.
In the New Testament this mixture is enlarged. John in the spirit saw a vision of the great Babylon (Rev. 17:3-5). Babylon is decorated, gilded, with all the things of the New Jerusalem. The New Jerusalem is built with three precious materials: gold, precious stones, and pearls (Rev. 21:18-21). The great Babylon is gilded with gold, precious stones, and pearls. She gives people the appearance that she is the same as the New Jerusalem, but she is not built in a solid way with these precious things; she is only gilded with these treasures as ornaments for outward display. This is a deception intending to entice people. It is the harlot's false appearance.
The difference between apostate Christendom and the genuine church is that one is a mixture, but the other is pure. In the New Jerusalem there is no mixture. Everything is pure. Revelation 21:18 says the city is pure gold. Also, the river of water of life is bright as crystal (Rev. 22:1). It is absolutely pure, without mixture.
The description in Revelation 17 says that this evil woman, the evil Babylon, holds a golden cup in her hand. But this golden cup is "full of abominations and the unclean things of her fornication" (v. 4). Outwardly it is golden, but inwardly there are evil things. It is a mixture. It has spiritual persons, some precious stones, like Madame Guyon, Father Fenelon, and Brother Lawrence, who give some outward appearance. But inwardly it is full of all kinds of evil.
The local churches have to be crystally transparent, with no mixture. Those of us who were in Christianity can testify concerning its hypocrisy and falsehood. Many good things are there to give a good appearance. But when you get into it, you see the evil mixture. We should not be deceived by the outward appearance of Babylon. What it has is an outward gilding, an outward decoration, but inwardly the situation is different.