That he heard Muawiya bin Abi Sufyan on the day of 'Ashura' during the year he performed the Hajj, saying on the pulpit, "O the people of Medina! Where are your Religious Scholars? I heard Allah's Apostle saying, 'This is the day of 'Ashura'. Allah has not enjoined its fasting on you but I am fasting it. You have the choice either to fast or not to fast (on this day).' "  

سَمِعْتُ رَسُولَ اللَّهِ ﷺ يَقُولُ هَذَا يَوْمُ عَاشُورَاءَ وَلَمْ يُكْتَبْ عَلَيْكُمْ صِيَامُهُ وَأَنَا صَائِمٌ فَمَنْ شَاءَ فَلْيَصُمْ وَمَنْ شَاءَ فَلْيُفْطِرْ  

This hadith is narrated on the authority of Hisham with the same chain of transmitters, but he made no mention in the first part of the hadith that the Messenger of Allah ﷺ used to observe fast, and said about the second part that he abandoned the (fast) of Ashura, and he who wished observed the fast and who wished otherwise abandoned it, and he did not hold it as the words of the Messenger of Allah ﷺ as mentioned in the narration transmitted by Jarir.  

وَكَانَ رَسُولُ اللَّهِ ﷺ يَصُومُهُ وَقَالَ فِي آخِرِ الْحَدِيثِ وَتَرَكَ عَاشُورَاءَ فَمَنْ شَاءَ صَامَهُ وَمَنْ شَاءَ تَرَكَهُ وَلَمْ يَجْعَلْهُ مِنْ قَوْلِ النَّبِيِّ ﷺ كَرِوَايَةِ جَرِيرٍ  

The Apostle of Allah ﷺ did not observe fast in the ten days of Dhul-Hijja.  

أَنَّ النَّبِيَّ ﷺ لَمْ يَصُمِ الْعَشْرَ  

[Machine] I heard the Messenger of Allah ﷺ saying, "This day, the day of Ashura, is not obligatory for you to fast. But I am fasting, so whoever wishes may fast on this day," referring to the day of Ashura.  

سَمِعْتُ رَسُولَ اللهِ ﷺ يَقُولُ هَذَا اليَوْمُ يَوْمُ عَاشُورَاءَ وَلَمْ يُكْتَبْ عَلَيْكُمْ صِيَامُهُ وَأَنَا صَائِمٌ فَمَنْ أَحَبَّ فَلْيَصُمْهُ يَعْنِي يَوْمَ عَاشُورَاءَ  

The Apostle of Allah ﷺ did not observe fast in the ten days of Dhul-Hijja. (Using translation from Muslim 1176b)   

أَنَّ النَّبِيَّ ﷺ «لَمْ يَصُمِ الْعَشْرَ قَطُّ»