The command in verse 27a is exactly the same as in 34.14; the promise in line b is literally “and you will dwell forever.” The Hebrew verb means to live somewhere, and the sense here is “live in the land,” that is, the Promised Land (New International Version “you will dwell in the land forever”; also Bible en français courant). Good News Translation has taken for ever to refer to the descendants of those to whom the promise is made. Anderson comments: “the Psalmist is thinking of the descendants of the righteous as being in possession of the ancestral inheritance” (see also Kirkpatrick). It does not seem correct to translate line b “and you will always have somewhere to live” (Biblia Dios Habla Hoy, New Jerusalem Bible, Traduction œcuménique de la Bible).
The parallelism on verse 28 is that of a general concept occurring in line a followed in line b by a specific. In this case the second noun saints contrasts with justice by being both more specific and plural. There is heightening of intensity in line b so that it can be translated in English, for example, as “The LORD loves that which is right, but what is more he will not abandon those who are faithful to him.”
In verse 28a justice translates mishpat (see comments on 7.6); for saints see comments on “the godly” in 4.3; preserved in 28c means “kept safe, protected”; for verse 28d see verse 9a; and verse 29 repeats the thought of verse 9b.
It should be noted that in verse 28c the Masoretic text is “they are protected forever”; following some manuscripts of the Septuagint, New English Bible has “The lawless are banished for ever” (similarly Bible de Jérusalem, New Jerusalem Bible, Bible en français courant, Biblia Dios Habla Hoy). This restores to the poem a strophe beginning with the letter ʿayin, the sixteenth letter, which is otherwise lacking. Though supported by some commentators (see Kirkpatrick, Briggs), this is rejected by Hebrew Old Testament Text Project (“A” decision).
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 .