The Book of Fasting (Kitab Al-Sawm)
Muslim :: Book 6 : Hadith 2511
This hadith has been narrated from Jarir on the authority of A'mash with the same chain of transmitters and he said (these words with a little bit of variation from the previous hadith): When (fasting) in Ramadan was (made) obligatory, he aban- doned it (the practice of observing fast on Ashura).