David
Psalm 119:140ESV·traditional attribution

Your promise is well tried, and your servant loves it.

John Calvin Reformed @genevareformer

PSALM 119 As this psalm treats of various matters, it is difficult to give an epitome of its contents. There are, however, two things which the prophet mainly aims at; the exhorting of the children of God to follow godliness and a holy life; and the prescribing of the rule, and pointing out the form of the true worship of God, so that the faithful...

Commenting on Psalm 119:1-176

Matthew Henry Presbyterian @wholebiblehenry

Here is, 1. David's great affection for the word of God: Thy servant loves it. Every good man, being a servant of God, loves the word of God, because it lets him know his Master's will and directs him in his Master's work. Wherever there is grace there is a warm attachment to the word of God. 2.

John Gill Reformed Baptist @doctorgill

The righteousness of thy testimonies is everlasting,.... Or, "for ever" (b). The righteousness which they require, or which they publish; the righteousness revealed in the Gospel, which is the righteousness of Christ; See Gill on Psa 119:142; give me understanding, and I shall live; an understanding of the testimonies of the Lord, of the word of God, the law of God, and Gospel of Christ...