“And I heard the number of them which were sealed: and there were sealed an hundreth and fourty and foure thousand, of all the tribes of the children of Israel.”
1611 King James Version (KJV)
7:4 Of the children of Israel - To these will afterwards be joined a multitude out of all nations. But it may be observed, this is not the number of all the Israelites who are saved from Abraham or Moses to the end of all things; but only of those who were secured from the plagues which were then ready to fall on the earth. It seems as if this book had, in many places, a special view to the people of Israel.
Re 7:4-8 And I heard the number of them who were sealed. The number first named is 144,000, twelve thousand from each of the twelve tribes of Israel. These numbers are not to be taken literally, but only signify that a great number, not a countless, but a part of each tribe of Israel, accepted the gospel. Of the tribes Ephraim appears under the name of Joseph (Re 7:8), and Dan is entirely omitted, a fact possibly due to the early falling away of Dan into idolatry (1Ki 12:26-30). The number twelve is preserved by counting Levi (Re 7:7). For another appearance of the 144,000, see Re 14:1.