This is not about sacred music per se. Yet, because improvisation is a longstanding practice within the realm of sacred music, it may be adjacent to it.

Rick Beato, the commenting host, knows it's an old art form, and knows that this is not the only couple of minutes of improvisation that's the most beautiful in the world, but those things aside, he knows his craft and is an engaging explainer of musical structures and the arts of making music (for folks unfamiliar with him, he's quite conversant in classical musical forms, along with jazz, rock et cet.; he's a musical omnivore as a musician and listener) - and in that role he can be among the models we may have for explaining improvisational music to people we might prefer not to have to engage but that would prudently try to engage:

The musician is Keith Jarrett, as recorded in 1973 - if you strongly prefer to skip the intro, the passage in question begins at the 2:30 mark:

https://www.youtube.com/watch?v=0BgXCDuqZvM