There are five verses in the Bible that refer to a “seal of God” or an object or person sealed by God (John 6:27; 2 Timothy 2:19; Revelation 6:9; 7:2; and 9:4). The word sealed in the New Testament comes from a Greek word that means “to stamp with a private mark” in the interest of keeping something secret or protecting or preserving the sealed object. Seals were used for official business: a Roman centurion, for instance, might have sealed a document that was meant only for the eyes of his superior. If the seal were broken, the one receiving the document would know that the letter had been tampered with or read by someone other than the sealer.
Revelation 7:3–4 and 9:4 refer to group of people who have the seal of God, and thus His protection, during the tribulation. During the fifth trumpet judgment, locusts from the Abyss attack the people of the earth with “power like that of scorpions” (Revelation 9:3). However, these demonic locusts are limited in what they can harm: “They were told not to harm the grass of the earth or any plant or tree, but only those people who did not have the seal of God on their foreheads” (Revelation 9:4). The individuals who are marked by God are preserved. The seal of God during the tribulation is the direct opposite of the mark of the beast, which identifies people as followers of Satan (Revelation 13:16–18).
Paul speaks of the seal of God in the context of foundational truth. He tells Timothy that false doctrines are circulating and some people are trying to destroy the faith of believers. Then he offers this encouragement: “Nevertheless, God’s solid foundation stands firm, sealed with this inscription: ‘The Lord knows those who are his,’ and, ‘Everyone who confesses the name of the Lord must turn away from wickedness’” (2 Timothy 2:19). The picture is of a building’s foundation that has been inscribed with two statements giving the purpose of the building. The church’s foundation has been laid (Ephesians 2:20), and the eternal “seal” or inscription sums up the two aspects of faith—trust in God and departure from sin (see Mark 1:15). The passage goes on to describe the contents of the great house so inscribed: vessels for honorable use and those for dishonorable use. “If anyone cleanses himself from what is dishonorable, he will be a vessel for honorable use, set apart as holy, useful to the master of the house, ready for every good work” (2 Timothy 2:21, ESV).
Jesus Christ bore the seal of God: “On him God the Father has placed his seal of approval” (John 6:27). Those who trust in Jesus also possess the seal of God, which is the Holy Spirit: “You also were included in Christ when you heard the message of truth, the gospel of your salvation. When you believed, you were marked in him with a seal, the promised Holy Spirit, who is a deposit guaranteeing our inheritance until the redemption of those who are God’s possession” (Ephesians 1:13–14). It is good to know that God’s children are sealed, secure, and sustained amid the wickedness of this transitory world.