The Pulpit Commentary
Hear me when I call, O God of my righteousness. Not "the God who imputes to me righteousness," as some render, but "the God who sees that I and my cause are righteous," and who wilt therefore certainly lend me aid. Thou hast enlarged me; or, made room for me—"set me at ease" In the language of the Old Testament, "straits" and "narrowness" mean trouble and affliction; "room," "space," "enlargement," mean prosperity. David has experienced God's mercies in the past, and therefore looks for them in the future (comp. Psa_3:7). When I woe in distress; literally, in [my] distress. Have mercy upon me, and hear my prayer. This is David's usual cry, repeated in a hundred varied forms throughout the Psalms (see Psa_5:2; Psa_6:2; Psa_9:13; Psa_27:7; Psa_30:10, etc.).

The Pulpit Commentary
O ye sons of men. "Sons of men "—beney ish—is not a mere periphrasis for "men." It is a title of some honour and dignity. Kay translates, "sons of the brave;" but that is scarcely the meaning. The phrase is rather equivalent to our "sirs" ('Speaker's Commentary.'). How long will ye turn my glory into shame? By your misconduct. See the clause which follows. The appeal is, perhaps, to Joab, Abishai, and others of David s own party, whoso proceedings were a disgrace to his reign, and tended to bring their master to shame rather than to honour. How long will ye love vanity, and seek after leasing? i.e. after lying. Joab's treachery and falsehood were notorious (2Sa_3:27; 2Sa_20:8-10).

The Pulpit Commentary
But know that the Lord hath set apart him that is godly for himself. The best order of the words would be, "Know that the Lord hath set apart for himself the man that is godly." The godly man is not contaminated by the evil doings of those who associate with him, and profess to act in his interest, if he neither authorizes nor condones their conduct. David had protested against Joab's proceedings on one occasion (2Sa_3:28), and never at any time pardoned them (1Ki_2:5, 1Ki_2:6). The Lord will hear when I call unto him Although I am disgraced (Psa_4:2), resisted, in many ways brought to shame, by you, yet still I am God's servant, set apart to his service, and therefore 1 shall be heard by him. He will hearken to and grant my prayer.

The Pulpit Commentary
Stand in awe, and sin not. The LXX. render, Ὀργίζεσθε καὶ μὴ ἀμαρτάνετε, "Be ye angry, and sin not;" and this meaning is preferred by Dr. Kay, Hengstenberg, and ethers. It may also seem to have the sanction of St. Paul in Eph_4:26. If we adopt it, we must suppose the exhortation to be addressed mainly to David's own followers, who are warned against excessive anger and its natural result, undue violence. Commune with your own heart upon your bed, and be still (compare St. Paul's injunction, "Let not the sun go down upon your wrath"). Anger cools if a little time be suffered to pass—if a night be allowed for reflection, and no action be taken till the morrow, Παύει γὰρ ὀργὴγ ὁ χρόνος (Aristotle). Selah. The second strophe being ended, another "pause" is to take place, during which the psalmist's exhortation may be made the subject of consideration.

The Pulpit Commentary
Offer the sacrifices of righteousness. Sacrifices of victims are scarcely meant; certainly not, if the time of the composition is that of David's exile, since victims could be offered nowhere but at Jerusalem. We may suppose a reference to those sacrifices which are most truly "sacrifices of righteousness," vie. "a broken spirit, a broken and a contrite heart," which God "will not despise" (Psa_51:17). And put your trust in the Lord. Sacrifice without faith is vain. Even "sacrifices of righteousness," to be of any service, must be accompanied by trust in the Lord.

The Pulpit Commentary
There be many that say, Who will show us any good? Pessimists are numerous in all ages. Among David's adherents in his times of distress (Psa_4:1) would be many who doubted and desponded, anticipating nothing but continued suffering and misfortune. Theft would ask the question of the text. Or the scope may be wider. Men are always seeking for good, but not knowing what their true good is. David points it out to them. It is to have the light of God's countenance shining on them. Lord, lift thou up, etc.; compare the form of Levitical benediction (Num_6:24-26), and see also Psa_31:15; Psa_80:3, Psa_80:7, Psa_80:19. If we bask in the sunshine of God's favour, there is nothing more needed for happiness.

The Pulpit Commentary
Thou hast put gladness in my heart. David is an example to the de-spending ones. Notwithstanding his sufferings and calamities, God has looked on him, and so "put gladness in his heart"—a gladness which far exceeds that of his adversaries. Though they are in prosperity, and have their corn and wine increased, and enjoy all the "outward material blessings promised to Israel—the wheat and the grape—for a supply of which he is indebted to the generosity of friends" (Kay), yet he would not change places with them. The spiritual joy which fills his own heart is preferable to any amount of material comforts and pleasures.

The Pulpit Commentary
I will both lay me down in peace, and sleep (comp. Psa_3:5). His confidence in God enables David to lay himself down calmly and tranquilly to sleep, whatever dangers threaten him. He seeks his couch, and at once (יחדּו) slumber visits him. No anxious thoughts keep him tossing on his bed for hours. For thou, Lord, only makest me dwell in safety. David has a satisfaction in thinking that it is God only who watches over him. All other help would be vain, superfluous. God alone brought Israel through the wilderness (Deu_32:12); God alone established Israel in Canaan (Psa_44:2, Psa_44:3). David feels that he needs no second helper and protector.