For the pillars (or, columns) of cloud and of fire to guide the Israelites (verse 39), see Exodus 13.21-22. Here the cloud is spoken of as a protective cover for them.
In verse 40a the Hebrew is “He asked,” which could refer to Moses. Revised Standard Version, New Jerusalem Bible, New English Bible, Die Bibel im heutigen Deutsch, New International Version, Biblia Dios Habla Hoy (all without textual note), and Good News Translation, New American Bible, Bible en français courant, New Jerusalem Bible, Traduction œcuménique de la Bible, Weiser (all with textual note) follow the ancient versions, which have the plural, They asked. Hebrew Old Testament Text Project says that “He asked” means the Israelites; but it should be noticed that nowhere in this strophe are they referred to by a singular pronoun or verb.39-42 Hebrew Old Testament Text Project (“C” decision) adds that the singular form could have God as subject, “God called,” or could be impersonal, “one asked/they asked.” It may be necessary to make verse 40a clear by saying, for example, “Moses asked God for meat…” or, if the plural is used, “the people asked Moses for meat….”
For the quails see 78.26-28; and for bread from heaven, that is, the manna, see 78.23-25.
The incident in verse 41 is probably what happened at Rephidim (Exo 17.1-6); see 78.15-16. The reader who is not acquainted with the historical account in Exodus may not know what opened the rock means, so it may be well to say “He caused a rock to split open….” In any case, a cross reference to Exodus 17.1-6 should be provided.
In verse 42 the psalmist recalls Yahweh’s holy promise to Abraham (see verse 9) as the reason for his continued help and sustenance to the people of Israel. Revised Standard Version he remembered his holy promise, and Abraham (following King James Version) is a possible translation of the Hebrew, but it seems more natural to read the text “his holy promise to Abraham,” as most translations do (see McCullough). The expression his holy promise must be recast in many languages, as it is difficult to speak of “holy” in relation to an utterance. However, here the meaning is God’s promise in the form of the covenant, and can be translated, for example, “he remembered his covenant with his servant Abraham” or “he did not forget what he had promised Abraham who served 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 .