Scripture teaches that Christ, through having died, risen, and ascended to the right hand of God, has purchased a glorious inheritance that is waiting for all those who believe in Him. But how do God’s people know this inheritance is waiting for them? In this sermon titled “The Sealing of the Spirit,” Dr. Martyn Lloyd-Jones explains from John 1:26–33 that God seals His people with His Holy Spirit as a guarantee. This sealing is something most believers would be familiar with in theory, but how many could explain what it actually is? Some base their explanation on their own experience, directly connecting the seal of the Holy Spirit to the work of producing the fruits of sanctification or to the baptism of the Holy Spirit. But both of these explanations pose problems to the understanding and experience of the work of the Holy Spirit. Drawing from various pertinent Scriptures, Dr. Lloyd-Jones brings forth the meaning, purpose, and comfort of the sealing of the Holy Spirit in believers’ hearts as a sign of ownership, security, and, ultimately, an authentication and confirmation for the believer of all God has promised.

http://www.mljtrust.org/sermons/the-sealing-of-the-spirit/