“And I saw another angel ascending from the east, having the seal of the living God: and he cried with a loud voice to the four angels, to whom it was given to hurt the earth and the sea,
  Saying, Hurt not the earth, neither the sea, nor the trees, till we have sealed the servants of our God in their foreheads.
  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.
  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…” etc., Rev. 7.2-5

This sealing of 144,000 Jews, 12,000 from every tribe (except Dan, which means to judge), with the seal of the living God in their forehead, is God’s counterpart of the Mark of the Beast. The phrase “the living God”, implies Jesus – the one risen from the grave, the one who is alive forevermore. These people are now God’s representatives on earth who will be alive after the devastation and purging that will come with the final judgments of the seventh seal. No judgment or disaster will harm them; the Antichrist will not be able to kill them. These are God’s remnants who will preach His Gospel during the Tribulation and beyond and be able to replenish the earth during the Millennium. God’s promise to the fathers, Abraham, Isaac and Jacob will be fulfilled in this group of saints. This is a critical group of mankind because it is through them that the promise of the prophets that Abraham’s seed will inherit the land of Israel will be fulfilled. The Jews shall inherit the land promised to Abraham. The holy covenant will be fulfilled and their Messiah, Jesus, shall reign on the throne of David forever. This promise has to be fulfilled in the flesh and it is this group that will man the farms and cultivate the fields of the New Israel; they will have families and on each appropriate holiday they will worship Jesus in the New Temple in the City of David, Jerusalem.

Heretical groups like the Jehovah’s Witnesses have claimed that there will be 144,000 “Super Saints”. This is one of the places in prophecy from which they have drawn their perverted view. It is true there will be 144,000 human beings elected and sealed by God, but they are 12,000 of each tribe of the nation Israel, and, though they are the core that will be left on earth after the Tribulation, they do not represent all that will survive. There will be a meager amount of “fortunate” ones who live through the Tribulation that will comprise the other nations and through them the nations of the earth will also be replenished during the infant years of the Millennium.  

Taken from the book Revelation Pure & Simple by Terry Myers Smith