From the additional notes to Charles Spurgeon's The Treasury of David, on Psalm 119, verse 25.
One does not wonder at the fluctuations which occur in the feelings and experience of a child of God— at one time high on the mountain, near to God and communing with God, at another in the deep and dark valley. All, more or less, know these changes, and have their sorrowing as well as their rejoicing seasons. When we parted with David last, what was he telling us of his experience? that God's testimonies were his delight and his counsellors; but now what a different strain! all joy is darkened, and his soul cleaveth to the dust. And there must have been seasons of deep depression and despondency in the heart of David— given as a fugitive and wanderer from his home, hunted as a partridge upon the mountains, and holding, as he himself says, his life continually in his hands. Yet I think in this portion of the Psalm there is evidence of a deeper abasement and sorrow of heart than any mere worldly suffering could produce.
He had indeed said, "I shall one day perish by the hand of Saul"; but, even in that moment of weak and murmuring faith, he knew that he was God's anointed one to sit on the throne of Israel. But, here there is indication of sin, of grievous sin which had laid his soul low in the dust; and I think the petition in Psalms 119:29 gives us some clue to what that sin had been: "Remove me from the way of lying." Had David— you may well ask in wonder— had David ever lied? had he ever deviated from the strait and honourable path of truth I am afraid we must own that he had at one time gone so near the confines of a falsehood, that he would be but a poor casuist and a worse moralist who should attempt to defend the Psalmist from the imputation. We cannot read the 27th chapter of the 1st of Samuel without owning into what a sad tissue of equivocation and deceit David was unhappily seduced. Well might his soul cleave to the dust as he reviewed that period of his career; and though grace did for him what it afterwards did for Peter, and he was plucked as a brand out of the burning, yet one can well imagine that like the Apostle afterwards, when he thought thereon he wept, and that bitterly. Barton Bouchier.