Describing a ruler as a shepherd of his people was not an original image when this psalm was composed; it was a conventional royal metaphor used across the ancient Near East, applied to Mesopotamian kings and Egyptian pharaohs alike in royal inscriptions predating and surrounding ancient Israel, so a psalm traditionally ascribed to David, himself remembered in the biblical narrative as a literal shepherd before becoming king, draws on and personalizes an image that was already common royal vocabulary across the region rather than inventing the shepherd king association from nothing. What the psalm does distinctively is invert the metaphor's usual direction, describing God as the shepherd of the individual speaker rather than a king as shepherd of his subjects, a personalization of a public royal image into private devotional address that helps explain the psalm's enduring intimacy for individual readers across many centuries and cultures.
The psalm's English reception is inseparable from one specific translation, the King James Version of 1611, whose rendering, now in the public domain and freely quotable unlike modern copyrighted translations, fixed phrasing that has shaped English religious and even secular vocabulary far beyond liturgical use, appearing in eulogies, literature and popular culture regardless of the speaker's own religious affiliation. Its near universal use at funerals across a very wide range of Christian denominations, and its adoption in Jewish practice as well, reflect a text whose brevity and psychological directness have let it travel across doctrinal boundaries with unusually little friction compared to longer or more theologically specific psalms.