A promise is a promise

"This is a point of great importance: even a pedigreed dog searches out his place under the dining table, regardless of kicks, not because of canine abjection but out of loyalty and faith; and even coldly calculating people do not succeed half so well in life as those with properly blended temperaments who are capable of deep feeling for those persons and conditions that happen to serve their own interests."

The Man Without Qualities, by Robert Musil (1930)