Wallace notes that in the passive voice the subject is acted upon or receives the action expressed by the verb. The subject may or may not be aware of this action.(Greek Grammar Beyond the Basics, Wallace, Daniel B., p431)
The verb has the following meaning: /sphragÃzÅ ("to seal") signifies ownership and the full security carried by the backing (full authority) of the owner. "Sealing" in the ancient world served as a "legal signature" which guaranteed the promise (contents) of what was sealed. HELPS Word studies
It is also used in 2 Corinthians 1:22 and Ephesians 4:30 in the same context.
In 2 Cor 1:22 this is in the middle voice. This is defined by Wallace as emphasizing the action of the subject. The subject performs or experiences the action expressed by the verb in such a way that emphasizes the subject's participation (Wallace p414-415). In this passage that subject is Christ. He is the one sealing us in this passage.
In Ephesians 1:13, the believer, is being sealed by the Holy Spirit. The believer plays no part in this action of the Holy Spirit.
The reader will also note the progression of salvation in this passage.
First there is hearing the Word of truth...the gospel.
Next comes the faith....the believing.
Then comes the sealing by the Holy Spirit.
The first two the believer does...the last, the Holy Spirit does to the believer.
Notice also in Eph 1:14 the Holy Spirit has been given as a pledge of our future inheritance. The Greek gives the meaning of earnest money. It is a deposit which guarantees the balance will be paid.
In both 2 Cor 1:22 and Eph 1:13 we see that the sealing is either done by Christ or the Holy Spirit. The believer is not responsible for the sealing. It is initiated from Heaven.
I cannot find any passage in the New Testament that ever says the believer is unsealed by the Holy Spirit or that the believer can unseal what has been sealed by the Spirit.
For the believer in Christ your salvation is secure as noted in these verses.
I give thanks to God for His lavish generosity towards us.
I’m keeping that for future reference.
That was AWESOME.
Here is an appropriate OT "type":
Then the Lord shut him in. Gen 7:16b