Sunan Abi Dawud

Narrated Umayyah b. Khalid: When Khalid al-Qasri was made ruler (of Hijaz and Kufah), he doubled the measure of sa'. The sa' then measured sixteen rotls. Abu Dawud said: Muhammad b. Muhammad b. Khattab was slain by Negroes in confinement. He said while signing with his hand: ""in this way"". Abu Dawud extended his hand and turned his palms towards earth and said: I saw him in the dream and asked him: How did Allah deal with you ? He replied: He admitted to Paradise. I said: Your detention did not harm you