Cast me not away from thy presence - That is, Do not reject me, or cast me off entirely; do not abandon me; do not leave me in my sin and sorrow. The language is derived from the idea that true happiness is to be found in the “presence” of God, and that to be exiled from him is misery. Compare Psalms 16:11, note; Psalms 31:20, note. See also Psalms 140:13.
And take not thy holy Spirit from me - It is not certain that David understood by the phrase “thy Holy Spirit” precisely what is now denoted by it as referring to the third person of the Trinity. The language, as used by him, would denote some influence coming from God producing holiness, “as if” God breathed his own spirit, or his own self, into the soul. The language, however, is appropriate to be used in the higher and more definite sense in which it is now employed, as denoting that sacred Spirit - the Holy Spirit - by whom the heart is renewed, and by whom comfort is imparted to the soul. It is not necessary to suppose that the inspired writers of the Old Testament had a full and complete comprehension of the meaning of the words which they employed, or that they appreciated all that their words might properly convey, or the fullness of signification in which they might be properly used in the times of the Gospel. Compare the notes at 1 Peter 1:10-12. The language used here by David - “take not” - implies that he had been formerly in possession of that which he now sought. There was still in his heart that which might be regarded as the work of the Spirit of God; and he earnestly prayed that that might not be wholly taken away on account of his sin, or that he might not be entirely abandoned to despair.