Revelation 7:4-8

7:4-8 And I heard the number of those who were sealed, one hundred and forty-four thousand were sealed from every tribe of the sons of Israel. Of the tribe of Judah twelve thousand were sealed; of the tribe of Reuben, twelve thousand; of the tribe of Gad, twelve thousand; of the tribe of Asher, twelve thousand; of the tribe of Naphtali, twelve thousand; of the tribe of Manasseh, twelve thousand; of the tribe of Simeon, twelve thousand; of the tribe of Levi, twelve thousand; of the tribe of Issachar, twelve thousand; of the tribe of Zebulun, twelve thousand; of the tribe of Joseph, twelve thousand; of the tribe of Benjamin, twelve thousand.

Those who are to be brought safely through the great tribulation are sealed upon their foreheads. The origin of this picture is very likely in Ezekiel 9:1-11 . In Ezekiel's picture, before the final slaughter begins, the man with the inkhorn marks the forehead of those who are faithful and the avengers are told that none so marked must be touched ( Ezekiel 9:1-7 ).

The idea of the king's seal would be very meaningful in the East. Eastern kings wore a signet ring whose seal was used to authenticate documents as really coming from the king's hand and to mark that which was the king's personal property. When Pharaoh appointed Joseph his prime minister and representative, he gave him his signet ring in token of the authority which had been delegated to him ( Genesis 41:42 ). So Ahasuerus gave his signet ring, first to Haman and then, when Haman's wicked schemes were unmasked, to Mordecai ( Esther 3:10 ; Esther 8:2 ). The stone which shut Daniel into the lion's den was sealed ( Daniel 6:17 ), as was the stone with which the Jews sought to make the tomb of Jesus secure ( Matthew 27:66 ).

Very commonly a seal indicated source or possession. A merchant would seal a Package of goods to certify that it belonged to him; and the owner of a vineyard would seal jars of wine to show that they came from his vineyard and with his guarantee.

So here the seal was a sign that these people belonged to God and were under his power and authority.

In the early church this picture of sealing was specially connected with two things. (a) It was connected with baptism which was regularly described as sealing. It is as if, when a person was baptized, a mark was put upon him to show that he had become the property and the possession of God. (b) Paul regularly talks about the Christian being sealed with the gift of the Holy Spirit. The possession of the Holy Spirit is the sign that a man belongs to God. The real Christian is marked out by the seal of the Spirit which enables him to have the wisdom and the strength to cope with life in a way beyond the attainment of others.