Musannaf Ibn Abi Shayba 33:1380

Abu Usama narrated to us, from Sulayman ibn al-Mughira, from Thabit, who said: Abu Barza used to dress in simple clothing, and 'A'idh ibn 'Amr al-Muzani used to wear fine clothing. He said: A man came to one of them and said, "Do you not see your brother wearing such and such, and he avoids your style of clothing?" He replied, "And who is able to be like so-and-so? Because of the virtue of so-and-so, such and such; because of the virtue of so-and-so, such and such; because of the virtue of so-and-so, such and such." He said: And he came to the other and said the same thing.