Musnad Ahmad 448:12

Qutaybah ibn Sa'id narrated to us, he said: Ibn Lahi'ah narrated to us, from Yazid ibn Abi Habib, from Abu al-Khayr, he said: Maslamah ibn Mukhallad—and he was the governor of Egypt—offered Ruwayfi' ibn Thabit to appoint him over the collection of tithes (al-'ushur). He said: "Indeed, I heard the Messenger of Allah, peace and blessings of Allah be upon him, say: 'The collector of the tax (al-maks) is in the Fire.'"