Cast me not away from your presence; and take not your holy Spirit from me.
Read Chapter 51
Augustine of Hippo
16. "Cast me not forth from Thy face" (ver. 11). Turn away Thy face from my sins: and "cast me not forth from Thy face." Whose face he feareth, upon the face of the Same he calleth. "And Thy Holy Spirit take not away from me." For in one confessing there is the Holy Spirit. Even now, to the gift of the Holy Spirit it belongeth, that what thou hast done displeaseth thee. The unclean spirit sins do please; the Holy One they displease. Though then thou still implore pardon, yet thou art joined to God on the other part, because the evil thing that thou hast committed displeaseth thee: for the same thing displeaseth both thee and Him. Now, to assail thy fever, ye are two, thou and the Physician. For the reason that there cannot be confession of sin and punishment of sin in a man of himself: when one is angry with himself, and is displeasing to himself, then it is not without the gift of the Holy Spirit, nor doth he say, Thy Holy Spirit give to me, but, "Take not away from me."
Spirit of prophecy, which is not withdrawn, except for some crime. (Origen) (Huet. p. 35.)
David had been without this privilege, till his repentance. (St. Athanasius)
Yet St. Chrysostom and Theodoret maintain the contrary. (Calmet)
He prays for final perseverance, which is due to none, (Berthier) and that he may fall no more. (Worthington)