How do we know that the Holy Spirit seals believers?

The sealing of believers by the Holy Spirit is affirmed in Ephesians 1:13, which states, 'In whom ye also trusted, after that ye heard the word of truth, the gospel of your salvation, in whom also after that ye believed, ye were sealed with that Holy Spirit of promise.' This sealing signifies God's ownership and preservation of His people until the day of redemption, providing assurance of their salvation. The sealing is not an ongoing process but a completed act that is central to the believer’s identity in Christ.