Psalms 51:11

Cast me not away from Thy presence, for he had once felt the excruciating agony of being excluded from the mercy of God and feared a repetition of the experience, and take not Thy Holy Spirit from me, so that he would slip back into the impenitent condition of that one terrible year, persist in his opposition to God's gracious influence, and thus be lost. Every believer prays to the Lord to be preserved against the hardening of his heart which leads to rejection of the Gospel-message and to final destruction.