Definitions for "Introductory"
Serving to introduce something else; leading to the main subject or business; preliminary; prefatory; as, introductory proceedings; an introductory discourse.
serving to open or begin; "began the slide show with some introductory remarks"
serving as a base or starting point; "a basic course in Russian"; "basic training for raw recruits"; "a set of basic tools"; "an introductory art course"
Keywords:  vespers, psalm, liturgical, bless, lord
psalm Psalm 103 [104], "Bless the Lord, O my soul," which begins Vespers and, thereby, the liturgical cycle of each new day
Beginning or foundational learning.