Hermann Hesse said this quote

“ When I composed those verses I was preoccupied less with music than with an experience—an experience in which that beautiful musical allegory had shown its moral side, had become an awakening and a summons to a life vocation. The imperative form of the poem which specially displeases you is not the expression of a command and a will to teach but a command and warning directed towards myself. Even if you were not fully aware of this, my friend, you could have read it in the closing lines. I experienced an insight, you see, a realization and an inner vision, and wished to impress and hammer the moral of this vision into myself. That is the reason why this poem has remained in my memory. Whether the verses are good or bad they have achieved their aim, for the warning has lived on within me and has not been forgotten. It rings anew for me again to-day, and that is a wonderful little experience which your scorn cannot take away from me. ”