I have had Morning Prayer in my wedding music collection for quite a long time now. I remember thinking when I came across it that I was surprised it was included in the Royal Conservatory Grade 3 book and not in a higher grade. It comes from Tchaikovsky's 1878 collection "Album for the Young" which he subtitled "24 easy pieces (à la Schumann)". Schumann had done such a collection himself in 1848. Tchaikovsky composed this wonderful collection of music accessible to young players which also sound beautiful and deceptively sophisticated.
Morning Prayer is a simple piece for notes and rhythm, but requires a musical sensitivity and maturity to capture the quiet reverent mood. It is quite versatile as wedding music, particularly in a church setting. I often play it for prelude music, but it's equally as appropriate for a flower girl, or any of the wedding party's entrance.