'Beware of sitting with kings and worldly people, for in this there is the erosion of your religion and it will bring about hypocrisy in you, and this is a serious disease from which there is no cure. It will also engender hardheartedness and deprive you of true submission [to Allah]. You must stick to those people who are most like you and the middle classes of people, for it is with them that you find the true jewels [great talents].'