How does the sealing of the Spirit authenticate a believer's faith?

In Ephesians 1:13-14, the Holy Spirit's sealing acts as a divine mark of authenticity for the believer's faith. Just like a king's seal authenticates a document, the Holy Spirit's presence in a believer's life authenticates their conversion and relationship with God. This action of sealing indicates that the faith they possess is the real work of Christ in their hearts, as it is through the Spirit that one can genuinely know and declare that Jesus is Lord. Thus, the sealing not only confirms their conversion but also assures them of their standing in Christ.