From the tribe of Judah 12,000 were sealed, from the tribe of Reuben 12,000, from the tribe of Gad 12,000,

Numbers 1:5
These are the names of the men who are to assist you: From the tribe of Reuben, Elizur son of Shedeur;

Numbers 26:20
These were the descendants of Judah by their clans: The Shelanite clan from Shelah, the Perezite clan from Perez, and the Zerahite clan from Zerah.

Revelation 7:4
And I heard the number of those who were sealed, 144,000 from all the tribes of Israel:

Revelation 7:6
from the tribe of Asher 12,000, from the tribe of Naphtali 12,000, from the tribe of Manasseh 12,000,

Of the tribe of Juda were sealed twelve thousand. Of the tribe of Reuben were sealed twelve thousand. Of the tribe of Gad were sealed twelve thousand.