As understood by Good News Translation (see introduction to this psalm), this verse is a statement (Briggs, Oesterley, Kirkpatrick, Dahood, New English Bible, Bible de Jérusalem, New Jerusalem Bible, New Jerusalem Bible, Bible en français courant, Die Bibel im heutigen Deutsch, Traduction œcuménique de la Bible) and ends the first part of the psalm. Others take it as a request (Revised Standard Version, New American Bible, New International Version, An American Translation, Biblia Dios Habla Hoy). If taken as a request, it should be joined to the next verse.

Do not … withhold thy mercy from me must sometimes be rendered idiomatically; for example, “Do not fail to have a white heart for me” or “Do not stop being pained for me.”

In many languages it is not possible for qualities like love and faithfulness (Good News Translation “loyalty”) to perform acts. Therefore one must often shift from noun phrases to verb phrases in such cases; for example, “you will always keep me safe because you love me and are loyal to me.”

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 .