In Ephesians 1:13 the Bible says that “when you heard the word of truth, the gospel of your salvation, and believed in him, were sealed with the promised Holy Spirit.”
What does it mean to be sealed with the Holy Spirit?
A seal is an identifying mark often placed on a letter, contract, or another document. It showed that what was in the letter came from the person whose seal was on the outside. In the ancient world, cattle and even slaves were branded with a seal to show whom they belonged. This mark would deter people from stealing them because they had the seal upon them.
The Bible uses this term in a few different ways, and when considered together, they help provide a full picture of what Paul is after here in Ephesians. In the Old Testament, God set a sign on his chosen ones to mark them out or set them apart as his possession and to keep them from destruction (Ezek. 9:4–6). We read in Revelation 7:3 that God places a seal on his people to identify them and protect them from wrath. We also see that the guards put a large stone over the tomb of Jesus to seal it (Matt. 27:66) and of John being told to seal up the words of the prophecy (Rev. 22:10). This communicates security. We also read of God authenticating the relationship with his seal (John 6:27). This is similar to the concept of Abraham’s circumcision serving as a sign and a seal of his righteousness (Rom. 4:11).
If we put this together, we see that in the Scriptures a seal communicates ownership, protection, and a validation of the relationship.
But what is the seal in Ephesians 1? The seal is not a “what” but a “who”—take another look at v.13, “[you] were sealed with the promised Holy Spirit.”
The Holy Spirit is the Christian’s seal. He seals his people. God’s own Spirit comes to indwell or take up residence in the believer. And I think the nuances from above apply here. The promised Holy Spirit identifies God’s people as his inheritance. And the experience of the Holy Spirit in a believer’s life is proof to them, and a demonstration to others, of the genuineness of their faith. The Holy Spirit provides the inward assurance that they belong to God as children (cf. Rom. 8:15–16; Gal. 4:6).
Some other verses where we see this concept developed in the New Testament:
For you did not receive the spirit of slavery to fall back into fear, but you have received the Spirit of adoption as sons, by whom we cry, “Abba! Father!” The Spirit himself bears witness with our spirit that we are children of God. (Rom. 8:15–16)
But when the fullness of time had come, God sent forth his Son, born of woman, born under the law, to redeem those who were under the law, so that we might receive adoption as sons. And because you are sons, God has sent the Spirit of his Son into our hearts, crying, “Abba! Father!” (Gal. 4:4–6)
[A]nd who has also put his seal on us and given us his Spirit in our hearts as a guarantee. (2 Cor. 1:22)
And do not grieve the Holy Spirit of God, by whom you were sealed for the day of redemption. (Eph. 4:30)
By giving us the Holy Spirit, God seals or stamps us as his own at our conversion. And then the Holy Spirit continues to testify, authenticating the reality of this relationship by making us more and more like Jesus.
The God who has thus authenticated this relationship will most certainly protect his people through trials and difficulties. He will do this until he takes final possession of us, his inheritance, on the day of redemption, which is at the end (Eph. 1:14).
To be sealed with the Holy Spirit is the gracious gift of God, whereby he demonstrates the authenticity of the believer’s relationship with him and his authority, ownership, and commitment to his people.