(1) 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 practise them is charged on the ruling class in Judæa at that time, though, of course, also required in the conduct of every man; 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.

(2) Behave myself wisely.—Literally, I will look to a guileless way. The root “to look” is that from which maskîl (Psalms 32, title) comes; hence some here see a reference to music, or song. But the Authorised Version is probably right, since the analogy of such words as “provident,” “circumspect,” shows how the idea of caution and then wisdom arises from that of looking. The English idiom, “look to your ways,” illustrates the Hebrew here.
O when wilt thou come unto me?—This clause is so awkward, however translated, that some critics go the length of pronouncing it spurious. In the Old Testament, with the exception of Exodus 20:24, the coming of God to a person is associated with the idea of punishment or inquisition (Psalms 17:3); and to see a reminiscence of 2 Samuel 6:9 (“ How shall the ark of the Lord come to me?”) seems far-fetched. It is better, therefore, to take the verb as the third person feminine instead of second masculine, with “perfect way” as its subject. The only difficulty in the way of this rendering is the interrogative; but, as in Proverbs 23:22, it becomes a simple adverb of time, we may treat it so here: “I will give heed to a guileless way when it comes to me,” i.e., whenever a course of action arises, presenting an alternative of a right and wrong, or a better and worse, I will choose the better.
I will walk within my house.—This vow of an Eastern monarch should be read with the thought of the palace of a caliph at Bagdad, or a sultan at Constantinople, before the mind. But it is a reflection of universal application, that piety should begin at home, and religion show itself in the household as much as at church.

(3) I will set no. . . . . —Mark the wisdom of the
resolve in a despotic monarch, who has only to speak to effect whatever he has looked on with desire.
Wicked thing.—Thing (or, word) of Belial. (See Note on Psalms 41:8.)
I hate the work of them that turn aside.—Or, I hate the doing of false things, according as we take the word in the concrete or abstract.
It shall not cleave to me.—Such conduct shall not be mine.

(4) Froward.—See Note, Psalms 18:26.

(5) Whoso . . .—The “informer” and the “haughty favourite” are no unknown characters in an Oriental court.
Proud heart.—Literally, broad, that is, extended with pride. (Comp. Proverbs 21:4.) But LXX. and Vulg., “insatiable.”
Will not I suffer.—In Hebrew a simple and expressive “I cannot,” to which we can supply “bear,” from Jeremiah 44:22. (Comp. Isaiah 1:13 : “I cannot away with.”)

(7) Tarry in my sight—i.e., stand as a courtier in the royal presence. Comp. Homer:
“Hateful to me as gates of hell is he
Who hides one thing within his mind and speaks another.”

(8) Early.—Literally, in the morning: referring, as Perowne observes, to the Oriental custom of holding courts of law in the early morning (Jeremiah 21:12; 2 Samuel 15:2; Luke 22:66; John 18:28).
City of the Lord.—For similar expressions, see Psalms 46:4; Psalms 48:2; Psalms 48:8. The city must bear out its name in its character.