What Happened to Dan? Ephraim?

Why are they not a part of the 144,000? Joseph and Mannesseh are included...


And I heard the number of those who were sealed. One hundred and forty-four thousand of all the tribes of the children of Israel were sealed:

5 of the tribe of Judah twelve thousand were sealed;
of the tribe of Reuben twelve thousand were sealed;
of the tribe of Gad twelve thousand were sealed;
6 of the tribe of Asher twelve thousand were sealed;
of the tribe of Naphtali twelve thousand were sealed;
of the tribe of Manasseh twelve thousand were sealed;
7 of the tribe of Simeon twelve thousand were sealed;
of the tribe of Levi twelve thousand were sealed;
of the tribe of Issachar twelve thousand were sealed;
8 of the tribe of Zebulun twelve thousand were sealed;
of the tribe of Joseph twelve thousand were sealed;
of the tribe of Benjamin twelve thousand were sealed.