The LORD will strengthen him upon the bed of languishing: thou wilt make all his bed in his sickness.
Make his bed — Give him ease and comfort, which sick men receive by the help of those who turn and stir up their bed, to make it soft and easy for them.
 I said, LORD, be merciful unto me: heal my soul; for I have sinned against thee.
Heal — The soul is said to be healed, when it is pardoned and purged.
For — For I acknowledge that I have sinned.
 And if he come to see me, he speaketh vanity: his heart gathereth iniquity to itself; when he goeth abroad, he telleth it.
His heart — Even when he is with me, and pretends hearty affection, his heart is devising mischief against me.
 Yea, mine own familiar friend, in whom I trusted, which did eat of my bread, hath lifted up his heel against me.
Yea — These words were literally fulfilled in David, and yet the Holy Ghost looked farther in them, even to Christ and Judas, in whom they received a fuller accomplishment.
Lift up — A phrase implying injury, joined with insolency and contempt; taken from an unruly horse, which kicks at him that owns and feeds him.
 But thou, O LORD, be merciful unto me, and raise me up, that I may requite them.
Requite — Punish them for their wicked practices; which being now a magistrate, he was obliged to do.
 By this I know that thou favourest me, because mine enemy doth not triumph over me.
By this — Because hitherto thou hast supported me, and prolonged my days to the disappointment of their hopes.
 And as for me, thou upholdest me in mine integrity, and settest me before thy face for ever.
Settest — Or, hast confirmed me in thy presence, under thine eye and special care: to minister unto thee, as a king over thy people. And in regard of his posterity, the kingdom was established for ever.
 Blessed be the LORD God of Israel from everlasting, and to everlasting. Amen, and Amen.
Amen — Signifies an hearty assent and approbation, and withal an earnest desire of the thing, to which it is annexed. And as the psalms are divided into five books, so each of them is closed with this word; the first here: the second, Psalms 150:6, the doubling of the word shews the fervency of his spirit, in this work of praising God.