Ephesians 1:3-14 3 Blessed be the God and Father of our Lord Jesus Christ, who has blessed us in Christ with every spiritual blessing in the heavenly places, 4 even as he chose us in him before the foundation of the world, that we should be holy and blameless before him. In love 5 he predestined us for adoption as sons through Jesus Christ, according to the purpose of his will, 6 to the praise of his glorious grace, with which he has blessed us in the Beloved. 7 In him we have redemption through his blood, the forgiveness of our trespasses, according to the riches of his grace, 8which he lavished upon us, in all wisdom and insight 9 making known to us the mystery of his will, according to his purpose, which he set forth in Christ 10as a plan for the fullness of time, to unite all things in him, things in heaven and things on earth. 11In him we have obtained an inheritance, having been predestined according to the purpose of him who works all things according to the counsel of his will, 12so that we who were the first to hope in Christ might be to the praise of his glory. 13In him you also, when you heard the word of truth, the gospel of your salvation, and believed in him, were sealed with the promised Holy Spirit, 14who is the guarantee of our inheritance until we acquire possession of it, to the praise of his glory.
If God says I'm sealed, then sealed I am.
I'm not going to dare to call God a liar to his face and deny it.
Let me know how that works out for you.