Sahih Muslim 1127 b
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 abandoned it (the practice of observing fast on Ashura).
وَحَدَّثَنَا زُهَيْرُ بْنُ حَرْبٍ، وَعُثْمَانُ بْنُ أَبِي شَيْبَةَ، قَالاَ حَدَّثَنَا جَرِيرٌ، عَنِ الأَعْمَشِ، بِهَذَا الإِسْنَادِ وَقَالاَ فَلَمَّا نَزَلَ رَمَضَانُ تَرَكَهُ ‏.‏