The meaning of this verse is not clear in the context of the psalm. The subject of the action is not made explicit in the Hebrew, but it is most certainly the king, not Yahweh, as Revised Standard Version has it. Good News Translation, Bible en français courant, Die Bibel im heutigen Deutsch, and Traduction œcuménique de la Bible footnote make this explicit: “The king will drink.” Some conjecture the verse to be a fragment of another composition. It may refer to a part of the ritual of enthronement (see Toombs, Anderson).

To lift up his head (line b) is probably a sign of victory (see 3.3; 27.6). Most, like Revised Standard Version, translate quite literally; Biblia Dios Habla Hoy has “and the water will renew his strength.” He will lift up his head, which Good News Translation renders “strengthened, he will stand victorious,” can be expressed in some languages as “he will be great because he has defeated his enemies.” It is possible that in the last line therefore refers not just to the preceding line but to the whole psalm. Following this interpretation the last line may stand as a complete sentence (with a full stop at the end of the first line): “For all these reasons the king will be victorious.”

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 .