Revelation 7:2-4, “Then I saw another angel coming up from the east, having the seal of the living God. He called out in a loud voice to the four angels who had been given power to harm the land and the sea: ‘Do not harm the land or the sea or the trees until we put a seal on the foreheads of the servants of our God.’ Then I heard the number of those who were sealed: 144,000 from all the tribes of Israel.”

This is an end-time picture. Joel 2: 1,2,10 talks about “the day of the Lord…a day of darkness and of gloominess, a day of clouds and of thick darkness,…the earth shall quake before them; the heavens shall tremble: the sun and the moon shall be dark, and the stars shall withdraw their shining…” During the period of our Lord’s second presence, Jesus shall judge the national, social (earth) and religious systems (heavens). However, before our Lord destroys this present evil world (Galatians 1:4), he will seal a class of 144,000 in their foreheads.

What is a seal? In ancient days, people would use a seal to imprint their identification marks in hot wax. When the seal was removed, the wax would bear the designated image of the owner. So, pictorially, this imprint of God is formed in the forehead. We know our foreheads represent our minds and thoughts. Therefore, this class bears the holy mark of God in their minds. Their thoughts and ways are clearly manifest to all as the seal is shown on their faces. This holy group of people radiates the mind of Christ.

What people have Christ’s mind? I Cor. 2:7, 16 states, “…we impart a secret and hidden wisdom of God,…none of the rulers…understood this,…But we have the mind of Christ.” We, the faithful followers of our Lord, have the mind of Christ. Those who are of this unique class are but a “little flock.” Our Lord specially rewards those who are transformed into Christ’s likeness. He permits them to reign with Christ in His kingdom. Luke 12:32, “Fear not, little flock, for it is your Father’s good pleasure to give you the kingdom.”

Referring back to Revelation 7, the final, Armageddon phase of God’s judgment doesn’t start until the 144,000 of spiritual Israel have proven faithful, have the seal of God in their foreheads, to reign with Christ (see Revelation 20).

Additional Resources: 
Christian Questions Podcast Episode 1248: “What Will We Be Doing When We Get to Heaven? (Part I)”
Examining the privilege of heaven, why it is open and how to get there
Preview Video  CQ Rewind Show Notes

Christian Questions Blog: Who is part of the 144,000 in Revelation?