Charles Ellicott Commentary Psalms 101:1

"I will sing of lovingkindness and justice: Unto thee, O Jehovah, will I sing praises." — Psalms 101:1 (ASV)

Mercy and judgment — or, as some render, grace and right — are the especially requisite attributes of a good monarch, or of magistrates generally. (See Matthew 23:23, where the failure to practice them is charged on the ruling class in Judea at that time, though, of course, also required in the conduct of everyone; Micah 6:8.) Here, no doubt, as almost all commentators have seen, they are first regarded ideally as attributes of the Divine King.

“And earthly power doth then show likest God’s,
       When mercy seasons justice.”

Will I sing. — Better, will I play.

On the question of the connection of this verse with the rest of the psalm, see Introduction.