 While it is technically one of the elements of the vespers service prescribed for the senior reader (that is, the elder or abbot of a monastery, or in a parish the seniormost reader at the kliros), it is customarily read or chanted by a reader after the opening prayers of the service.The psalm is meant to be read or chanted in a plain style at services of vespers which are not part of a vigil.When vespers is served as part of a vigil, an abbreviated musical version is usually sung by the choir.