A slave dealt harshly with his master, so he [i.e. the master] said: “Indeed as you can see I exercise patience with this boy in order to train my soul- because if I exercise patience with the slave [whilst bearing] that which is hated, I will exercise more patience with other than him [i.e. when dealing with others]”.

[Source: Kitaab Uyoounul Akhbaar’ of Ibn Qutaybah (rahimahullaah): Vol: 1-page: 332]