Verses 21-22 flow together (see Revised Standard Version), and a translation may seek to preserve this form, if it is not too difficult for the readers.

In verse 21a forgot repeats the accusation made in verse 7. In verse 22a the land of Ham is the same as Egypt in verse 21b (see 78.51). And great things … wondrous works … terrible things (verses 21b, 22a-b) all mean the same thing, the miracles, the marvelous things that God did. Terrible things (verse 22b) is most inappropriate in English; it is better to say “surprising” (Biblia Dios Habla Hoy) or “awesome” (New Jerusalem Bible, New Jerusalem Bible, New International Version); see 99.3. For Red Sea see verse 7.

Verse 23 relates how Moses persuaded God to change his mind and not destroy the people of Israel for their idolatry (see Exo 32.9-14). There is an ellipsis in Revised Standard Version (also New International Version and others) which may be misleading. The thought is that God actually did threaten to destroy them, and would have done so had not Moses…. The figure used, stood in the breach, is that of warfare, where a soldier might stand in a break made in the wall by enemy soldiers, so as to keep them from entering the city. The figure stood in the breach and Good News Translation‘s “stood up against” are picturable images of Moses’ action; however, the action consisted mainly in speaking to God on behalf of the people. Accordingly, in many languages it will be clearer to say something like “Moses stood up and argued with God” or “Moses spoke with God and persuaded him.” The expression turn away his wrath from destroying them may have to be recast to say, for example, “to keep God, who was angry with them, from killing them” or “to convince God in his anger that he should not kill them.”

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 .