In verses 24-29 God promises to be with David always, to uphold him, bless him, and make him king over a mighty empire. The direct quotation of what God said to David is a long one (verses 19-37), and in some translations it may be helpful to make a break and reintroduce God as speaker; verse 24 can begin: “God also said, ‘I will love David….’ ”
In verse 24, as in verses 2, 14b, God’s faithfulness and … steadfast love are spoken of; here he pledges them to David for all time. In verse 24b the Hebrew is and in my name shall his horn be exalted (see verse 17b). In my name means “by means of my power (or, presence) with him.” His horn is a figure for power, strength (see also comments on 18.2; 75.4, 5). Die Bibel im heutigen Deutsch translates “Because I will be with him, his power will grow,” and Biblia Dios Habla Hoy has “and by means of me his power will grow”; Bible en français courant translates “I am the one who will make his power grow.” Good News Translation has shifted from the noun phrases in Revised Standard Version to verb phrases, just as many translators will be required to do. “I will make him always victorious” must in many languages be recast to say, for example, “I will always enable him to defeat his enemies.”
One of the typical devices for heightening poetic effect in parallel lines is the use of a metaphor in the second line, here horn be exalted. This effect may be translated by saying, for example, “Not only will I love him and be loyal to him, I will always help him defeat his enemies.”
David’s kingdom will reach from the sea to the rivers. Good News Translation and others take this to mean “from the Mediterranean to the Euphrates River” (see discussion of similar expressions in 72.8; 80.11). Some take the language to mean that David’s reign will be universal, the sea and the rivers standing for the limits of the whole world (see 24.2 and comments). It is probable, as Dahood maintains, that here, as in verse 13b, hand and right hand mean “left hand” and “right hand.” It is also possible that the psalmist is dealing more with poetic word pairs than with geographical space.
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 .