In the interest of full disclosure, despite following Tchaikovsky’s work I first heard this piece not very long ago.
I’ve always found choral music to be an exemplar of the most moving and powerful parts of the classical tradition, and Tchaikovsky offers something that is beyond even his usual mastery.
Of course, most people in the West know Tchaikovsky for his contributions in the form of the Nutcracker ballet–which has probably the largest cultural relevance and serves as a Christmas-time staple–or his rousing 1812 Overture. His Romeo and Juliet is instantly recognizable, though it is often used for its motifs and not attributed to him (e.g. played in very short snippets). Personally, I don’t particularly care for much of his music from the ballets, though his orchestral compositions appeal to me more.
Until recently, I was entirely unaware that Tchaikovsky had written any sacred music.
It’s quite beautiful, and one can see the premonitions of what would continue in the works of Pärt and other writers of modern sacred music in it.