In general I am wary of quotations - or, rather, I am wary of basing a world-view on one-sentence sayings - because they can be reductionist. But there are many which capture a personality well, or which expose the complexity of a situation, or which are just funny. Beethoven, though a musician who almost never wrote opera (though, of course, the Ninth Symphony has lyrics) and generally did not write songs, had his fair share of revelatory sayings. Here are my favorites:
"I despise a world which does not feel that music is a higher revelation than all wisdom and philosophy."
“Music is the mediator between the spiritual and the sensual life.”
“Music is the one incorporeal entrance into the higher world of knowledge which comprehends mankind but which mankind cannot comprehend.”
“What you are, you are by accident of birth; what I am, I am by myself. There are and will be a thousand princes; there is only one Beethoven.” - said to a Prince who, as you might guess, elicited the ire of Mr. Beethoven.
“No friend have I. I must live by myself alone; but I know well that God is nearer to me than others in my art, so I will walk fearlessly with Him.”
"The barriers are not erected which can say to aspiring talents and industry, 'Thus far and no farther.'"
And his dying words: "Applaud friends, the comedy is over."
While his music perhaps gives a stronger sense of who Beethoven is than his words do, it is also easy for our modern ears - which have grown accustomed to a different kind of music - to dismiss Beethoven as grumpy, violent, or sad. He is none of those things. His music is some of the most emotionally charged and passionate ever written, but he also composed some of the most humorous, joyful, and spiritual music of his era. What makes Beethoven so remarkable is that he manages to be all of those things - grumpy, humorous, violent, joyful, sad, and spiritual - all at once. He is an exquisitely human composer who knows how to reach into the depths of the human spirit, and to laugh while doing it.
(Though not so much on the joyful, playful side - at least not obviously so - this is an excellent recording of the "Appassionata" sonata. Do yourself a favor and at least listen to the last couple minutes, though of course the whole thing is amazing.)