The text puts before us:
I. A future experience embraced or anticipated by faith. It indicates the sustaining power of such anticipation. (1) The goodness of God is His kindness. Of the kindness of God we may remark: (a) it is natural; (b) it is infinite; (c) it is eternal; (d) it is perfect in quality; (e) it is the goodness which creates goodness. (2) The knowledge David had of the goodness of God was derived from three sources: (a) the history of its manifestation to man from his creation; (b) the story of its expression to David's own people and nation; (c) his own experience of it from his childhood. (3) David's faith rested (a) on the promises of God; (b) on the character of God; (c) on the uniform conduct of God as requiring that which is past; (d) his past and present experience.
II. See how David's faith wrought. (1) It occupied his thoughts pleasantly and profitably. (2) It saved him from the misery of despondency and despair. (3) It gave him courage in danger. (4) It made him patient. (5) It was his shield against many fiery darts and heavy thrusts. (6) It kept him from accounting life a burden and death an object of eager desire. (7) It checked any tendency to yield himself to his circumstances and to do "evil that good might come."
S. Martin, Comfort in Trouble,p. 20.
References: Psalms 27:13. Spurgeon, vol. xiii., No. 766; W. G. Horder, Christian World Pulpit,vol. xxviii., p. 82.