It is impossible to tell who is being addressed, whether the psalmist’s accusers (addressed in verses 2-4) or people in general. It may be that the Selah at the end of verse 4 indicates a shift in address, but this is not certain. Commentators are divided on the subject. Revised Standard Version and Good News Translation division of strophes implies that the same people are still being addressed (also New English Bible, New American Bible, Biblia Dios Habla Hoy, Bible en français courant).
Right sacrifices are those required by the Law, those that Yahweh commanded (see Traduction œcuménique de la Bible). Some understand the Hebrew phrase “sacrifices of righteousness” to mean sacrifices offered in the right spirit (so Delitzsch, Kirkpatrick); New Jerusalem Bible has “Loyally offer sacrifice”; another possible rendering is “Offer sacrifice in the right way.”
For an understanding of the sacrificial system in the Old Testament, translators should consult a Bible dictionary; see also the chart of types of sacrifices in A Translator’s Handbook on Leviticus, page 5. There were different kinds of sacrifice, and animal sacrifices included the killing of cattle, sheep, goats, doves, and pigeons. A sacrificial bird or animal was brought to the altar, where it was killed by a priest, burned, and thereby offered to God as a gift. The Hebrew term used in verse 5 will occur in 27.6; 50.8; 51.19; 106.28; and 107.22.
Sacrifices presents few problems in translation where sacrificial rituals are practiced or at least known. Where a descriptive expression must be used, “gifts killed for God” or “gifts that are burned and given to God” offer reasonable alternatives. The translation put your trust in the LORD frequently requires a “heart” idiom such as “having a thick heart for someone” or “placed one’s heart upon another.” The two lines may be rendered “Give to the LORD the burned gifts which he requires, and rest your heart upon him.”
Quoted with permission from Bratcher, Robert G. and Reyburn, William D. A Handbook on the Book of Psalms. (UBS Helps for Translators). New York: UBS, 1991. For this and other handbooks for translators see here .