Holy Spirit is the agent of sealing, you should know.
How to know that the Holy Spirit is the agent of sealing according to the Bible as reference in the Book of Revelation 7:2-3. Then, the seal is pronounced in the Book of Isaiah 8: 16. Some versions of the Bible refers to seal as; Sign or Mark so when you see it like that, is still the same thing. Allow the Bible to lead you through and never be confused again.