13 In Him you also trusted, after you heard the word of truth, the gospel of your salvation; in whom also, having believed, you were sealed with the Holy Spirit of promise,
you were sealed
“Were sealed” is the past point at which we became believers. The Greek indicates that the sealing by the Holy Spirit of believers takes place at the moment they hear and believe.
The idea of “sealed” carries the idea of security (Mt 7:66; Eph 4:30). A seal gives validity to a contract. It is a sign that we belong to God. Owners of the first century branded both cattle and slaves to show to whom they belonged. When God gives believers the seal of the Spirit, He stamps them as His own. He does this until He takes full possession of them.
A seal in ancient practice was a sign of ownership. People sealed letters with wax and then pressed a ring or another object with an image onto the wax. We are God’s; we bear His image. We have the mark of His ownership on us. Sealing speaks of security, identity, and ownership.
“Sealed” in the Greek indicates that the sealing took place at one point in the past, that God did the sealing, and that it was a fact that it occurred in the past (aorist, passive, indicative).
The sealing of the Holy Spirit is seen three times in the New Testament (here, Eph 4:30, and 2 Co 1:21-22).
with [even] the Holy Spirit
God the Father sealed us with Holy Spirit. “Sealed” indicates official confirmation of salvation by the indwelling Holy Spirit.
God promised a time when He would “pour out His Spirit on all flesh,” both Jew and Gentile (Joel 2:28).
The sealing of the Spirit is the guarantee that we will arrive safely in heaven for the redemption of our bodies.
At the point of salvation, God seals us and brands us as His own. This is not something that occurs subsequent to salvation; it transpires at the time we believe in Christ.
The Holy Spirit takes up residence when someone becomes a Christian, marking the person as God’s own. This is a truth that we do not directly experience; we know it is true because God said it is true. Cattlemen put a brand on their livestock to show that those animals belong to a particular spread or ranch. The sealing of the Holy Spirit shows that the believer belongs to God forever. God has given us assurance of eternal life. Words of men are unreliable, but we can completely trust God’s words.