"And you also were included in Christ when you heard
the word of truth, the gospel of your salvation.
Having believed, you were marked in him with a seal,
the promised Holy Spirit,
who is a deposit guaranteeing our inheritance
until the redemption of those who are God's possession--
to the praise of his glory."
Yet, practically speaking, what does that mean? Here are a couple of illustrations:
In days of yore, when the king wanted to send an important message meant "For your eyes only," he would fold it and pour sealing wax over the fold. While the wax was still hot, he would stamp it with his seal (usually his signet ring). Anyone tampering with the seal before it reached the intended recipient would suffer the deadly consequences! The contents of that message were safe!
Even before God sent His indwelling Holy Spirit to seal believers, He is known to have put hedges of protection around them so evil couldn't get at them. Consider His servant Job. When God praised Job's uprightness, Satan countered that Job only "shunned evil" because God had put a hedge (or seal) around him and his household and all that was his. As a test, God allowed Satan access to Job. You know the rest of the story.
Today, we have the abiding presence of God's Holy Spirit and He has promised never to leave us or forsake us. We are sealed until the day of redemption, or, in other words, until He takes us Home. No one can get at us without His permission and, even if He should allow it, He is there to protect us from all evil.
I like knowing that I have been sealed with the signet ring of the Most High God. Don't you?