Revelation 7:4 And I heard the number of them which were sealed: and there were sealed an hundred and forty and four thousand of all the tribes of the children of Israel.
5 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.
6 Of the tribe of Aser were sealed twelve thousand. Of the tribe of Nepthalim were sealed twelve thousand. Of the tribe of Manasses were sealed twelve thousand.
7 Of the tribe of Simeon were sealed twelve thousand. Of the tribe of Levi were sealed twelve thousand. Of the tribe of Issachar were sealed twelve thousand.
8 Of the tribe of Zabulon were sealed twelve thousand. Of the tribe of Joseph were sealed twelve thousand. Of the tribe of Benjamin were sealed twelve thousand.
Here in verse 4 thru 8 we see where the 144000 come from . They chosen by God from the 12 tribes of Israel and are Jews. They are some religions teaching today that you can work hard for God and become one of these chosen to be in the 144000. Also as we later in chapter 14 these 144000 were male virgins. Again they are sealed by God to preach the gospel and they cannot be hurt.