God's church is compared to the Jewish temple. Regardless of our ethnicities and nationalities, we are all as stones, hewed by Christ, then built into a single temple. Reference: E.G. White, "The Upward Look," p. 281.

Full text of the devotional: “God’s Church a Temple,” September 24

Ye also, as lively stones, are built up a spiritual house, an holy priesthood, to offer up spiritual sacrifices, acceptable to God by Jesus Christ. 1 Peter 2:5.

The Jewish Temple was built of hewn stones quarried out of the mountains, and every stone was fitted for its place in the Temple, hewed, polished, and tested, before it was brought to Jerusalem. And when all were brought to the ground, the building went together without the sound of ax or hammer. This building represents God’s spiritual temple, which is composed of material gathered out of every nation, and tongue, and people, of all grades, high and low, rich and poor, learned and unlearned. These are not dead substances, to be fitted by hammer and chisel. They are living stones, quarried out from the world by the truth; and the great Master Builder, the Lord of the temple, is now hewing and polishing them, and fitting them for their respective places in the spiritual temple. When completed, this temple will be perfect in all its parts, the [object of] admiration of angels and men, for its builder and maker is God.

Let no one think that there need not be a stroke placed upon him. There is no person, no nation, that is perfect in every habit and thought. One must learn from another. Therefore God wants the different nationalities to mingle together, to be one in judgment, one in purpose. Then the union that there is in Christ will be exemplified.

I was almost afraid to come to this country, because I heard so many say that the different nationalities of Europe were peculiar, and had to be reached in a certain way. But the wisdom of God is promised to those who feel their need and who ask for it. God can bring the people where they will receive the truth. Let the Lord take possession of the mind, and mold it as clay is molded in the hands of the potter, and these differences will not exist. Look to Jesus, brethren; copy His manners and spirit, and you will have no trouble in reaching these different classes. We have not six patterns to follow, nor five. We have only one, and that is Christ Jesus. If the Italian brethren, the French brethren, and the German brethren try to be like Him, they will plant their feet upon the same foundation of truth; the same Spirit that dwells in one will dwell in the other—Christ in them, the hope of glory. I warn you, brethren and sisters, not to build up a wall of partition between different nationalities. On the contrary, seek to break it down wherever it exists. We should endeavor to bring all into the harmony that there is in Jesus, laboring for the one object—the salvation of our fellow men.—Manuscript 135, 1901, September 24, 1885, “Unity Among Different Nationalities,” a sermon given in Basel, Switzerland.