Brahms is known to have had a sharp tongue. In his later life he was accused of never ceasing an opportunity of insulting others. Actually he himself once made a similar remark, leaving a social gathering saying: "If there are anyone I haven't insulted tonight I ask for forgiveness".
In many biographies he has been accused of being rather rude as well as unsociable. It maybe true to a certain degree but maybe there were nuances. His quotes are an invaluable and primary source to a glimpse into the man Johannes Brahms as well as his impressions of his contemporaries and the time he lived in.
Brahms was very reluctant in commenting on his own music. This modern impression may be due to the fact that he self-censured his letters in fear of future biographers and we therefore have little hard evidence of such comments. But it may also be true because he felt that music should talk for itself and therefore did not make such comments. A famous quote underlines it brilliantly in favour of the latter: "Only a creating genius can be convincing in music".
Nevertheless there are numerous quotes and recollections that can shed light on his own view of his music, their creation and performance.
"I'm in love with music, I think only music - if this continues I will dissolve into a chord and vanish into the air"
ON PRACITAL EXECUSION OF MUSIC
"Regarding tempo, I regret many pedantic directions in my earlier works"
"Modifications of tempo (rubato) is nothing new and must be done con discrezione"
"For me, a thinking, sensible singer can, with no hesitation, change a note that for some reason or another is presently out of comfortable range, as long as the declamation stays correct and the accentuation is not harmed"
"The Lied now sails on such a wrong course that one cannot firmly enough inculcate one self an ideal - that is for me the folksong "
ON OTHER COMPOSERS
"Unapproachable, that is the only possible thing to be when it comes to Listz"
"Bruckner, it is a hoax that will be forgotten a year or two after my death"
"There the man composes like he was Schubert, but then he remembers he's a Wagnerian, and suddenly everything is ruined" (about Bruckner)
If I was to write an opera, I's rather do it in Mozart style than in Wagner style"
It is soothing to the soul" (about Bach's Goldberg Variations)