Charles H. Spurgeon on Psalms 30:1

Thou hast lifted me up. (yntyld) The verb is used, in its original meaning, to denote the reciprocating motion of the buckets of a well, one descending as the other rises, and vice versa; and is here applied with admirable propriety, to point out the various reciprocations and changes of David's fortunes, as described in this Psalm, as to prosperity and adversity; and particularly that gracious reverse of his afflicted condition which he now celebrates, God having raised him up to great honour and prosperity; for having built his palace, he "perceived that the Lord had established him king over Israel, and that he had exalted his kingdom for his people Israel's sake." 2Sa 5:12. Samuel Chandler.