Musnad Ahmad 626:22

Muhammad ibn Ja‘far narrated to us, Shu‘bah narrated to us, from Isma‘il, from Qays, from al-Mughirah ibn Shu‘bah, who said: No one asked the Prophet, may Allah bless him and grant him peace, more than I asked him. He said: "It will not harm you." I said: "They say that he has a river and such and such." He said: "He is more insignificant to Allah than that."