In my opinion, the unpardonable sin is refusing the free gift of life and love of god.
Its rejecting unconditional love.....its unforgivable because if God forgives it, he has to let you go and stop loving you. He will understand why you reject it, whether it be bad experiences, or a bitter heart. And god will not let a person go, he will always try to save you and will always love you.
The Day of the Lord
…8Beloved, do not let this one thing escape your notice: With the Lord a day is like a thousand years, and a thousand years are like a day. 9The Lord is not slow to fulfill His promise as some understand slowness, but is patient with you, not wanting anyone to perish but everyone to come to repentance. 10But the Day of the Lord will come like a thief. The heavens will disappear with a roar, the elements will be destroyed by fire, and the earth and its works will be laid bare.
God knows you, underneath your masks, underneath your anger and bitterness. He wants you to get to know him.
