Doctrine of the Sacred Scripture # 11
11. The seventh chapter in the book of Revelation tells us that one hundred and forty-four thousand [of the servants of God] were sealed, twelve thousand out of each tribe of Israel — out of the tribes of Judah, Reuben, Gad, Asher, Naphtali, Manasseh, Simeon, Levi, Issachar, Zebulun, Joseph, and Benjamin.
The spiritual meaning of this is that all people are saved who have the church in them from the Lord. For in the spiritual sense to be sealed or to have a mark placed on the forehead means, symbolically, to be acknowledged by the Lord and saved. The twelve tribes of Israel symbolize all people of the church. The numbers 12, 1,200, and 144,000 symbolically mean all people. Israel symbolizes the church. And each of the tribes symbolizes some particular aspect of the church.
People who are not aware of the spiritual content of these words may suppose that only that number of people are to be saved, and these solely from the Israelite and Jewish nations.