Charles H. Spurgeon on Psalms 16:9

He clearly foresaw that he must die, for he speaks of his flesh resting, and of his soul in the abode of separate spirits; death was full before his face, or he would not have mentioned corruption; but such was his devout reliance upon his God, that he sang over the tomb, and rejoiced in vision of the sepulchre. He knew that the visit of his soul to Sheol, or the invisible world of disembodied spirits, would be a very short one, and that his body in a very brief space would leave the grave, uninjured by its sojourn there; all this made him say, "my heart is glad," and moved his tongue, the glory of his frame, to rejoice in God, the strength of his salvation. Oh, for such holy faith in the prospect of trial and of death! It is the work of faith, not merely to create a peace which passeth all understanding, but to fill the heart full of gladness until the tongue, which, as the organ of an intelligent creature, is our glory, bursts forth in notes of harmonious praise. Faith gives us living joy, and bestows dying rest. "My flesh also shall rest in hope."