In these two verses the psalmist asks God to protect him from temptation to speak evil (verse 3) or do evil (verse 4). Verse 3 is composed of two parallel and synonymous lines; in poetic language the psalmist asks God to Set a guard and to keep watch at his mouth, at the door of (his) lips, so that he will not utter any sinful words. The word translated door occurs only here in the Old Testament. In languages in which the metaphors of verse 3 will be readily understood, they should be used. However, the word “mouth” has a wide range of meanings in many languages, and there is considerable probability of misunderstanding. If that is the case, the translator may find an equally good metaphor, and if that fails, it will be best to say, for example, “Do not let me speak evil words.” There is no intensification between the two lines of verse 3. This means the translator has more freedom to keep both lines or to reduce them to one, if that is stylistically necessary.
In verse 4 the psalmist prays that God will keep him from doing wrong. The Hebrew text has four half-lines (see Revised Standard Version); Good News Translation has reduced them to three, avoiding needless repetition (also Biblia Dios Habla Hoy). The language is “Do not turn my heart to an evil matter (or, word),” a plea that recalls the petition in the prayer taught by Jesus, “lead us not into temptation.” The thought behind the language is the possibility that God may test a person by allowing that person to be faced with sin. The word translated any evil is literally “an evil word (or, matter),” and so it may be taken to mean “word” (so Dahood, Bible de Jérusalem, New Jerusalem Bible); New English Bible has “sinful thought,” which is possible, since heart was thought of as the organ of thinking.
Good News Translation has combined Revised Standard Version wicked deeds and iniquity into “in their wickedness.” This may have to be recast in some languages to say, for example, “in the evil things they do.”
The last line, let me not eat of their dainties, is a prayer that God will not allow the psalmist to take part in the feasts of evil people. It can be understood as a resolve, “I shall not sample their delights!” (New Jerusalem Bible). These feasts could have been purely social affairs, but it is possible that they were religious meals, in which case they would have been, in this context, meals at sacrifices offered to idols (see 69.22). The word translated dainties occurs only here in the Old Testament. Since eat of their dainties and Good News Translation‘s “take part in their feasts” refers to pagan religious eating, it will be necessary in many cases to make this clear; for example, “Do not let me eat with them at their religious feasts,” or “… when they eat to worship their gods,” or “Keep me from eating….”
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 .