Albert Schweitzer pointed out (in https://www.amazon.com/dp/0486216314 ) that in many cases it's hard to understand Bach's music without understanding the lyrics. The mood of the music will change from cheerful to somber (or whatever) seemingly randomly, but if you understand the lyrics, it's not random.
However a counterexample from my own life: I only learned German starting in my late 20s and when, 10 years later I heard the Matthäus-Passion and could understand the lyrics I wept...and I don't even know much about christianity.