He had said so bravely, and that is why one can trust Beethoven when he says other things. One device which composers use is to state a theme unequivocally and then repeat it so that it is well established in the mind of the listener. Then, instead of repeating it again at a point where this might be expected, the composer proceeds to prevaricate, and heighten the tension of expectation by altering the original rhythm, harmony or tempo in such a way that the pattern seems almost shattered. When the original theme finally does return, our relief at order being restored is all the greater. The peculiar thing about the blues as a musical form is how little such prevarication there is.
Blues music is almost all theme and no, or very little, variation.
But I won't be blue always. You know the sun's gonna shine In my back door one day. In my doggone life before. My good girl, She's gonna quit me. It sure does grieve my mind.