The assurance of Christ is to receive forgiveness and then to go and sin no more. Bear fruit with repentance. How many times can one be forgiven for the same sin or the tyranny of one’s passions which wage war against the flesh. Hardening one’s heart enough grieves God’s Spirit to a point of losing the deposit or seal of our assurance. The story of Saul reminds us that although anointed by God, the Holy Spirit was taken away because of his wilful disobedience. Then again David wasn’t perfect either. The difference was he understood repentance.