كتاب الصيام
13  
The Book of Fasting
(21)
Chapter: Whoever eats on'Ashura, let him refrain (from eating) for the rest of the day
(21)
باب مَنْ أَكَلَ فِي عَاشُورَاءَ فَلْيَكُفَّ بَقِيَّةَ يَوْمِهِ ‏‏
Sahih Muslim 1136 b

Khalid b. Dhakwan reported:

I asked Rubayyi' daugther of Mu'awwidh about fasting on the day of 'Ashura. Thereupon she said: The Messenger of Allah (may peace he upon him) sent his messenger to the villages of the Ansar, and the rest of the hadith is the same (but with this variation that one of the Companions) said:" We used to make toys out of wool and took (them to the mosque) along with us. When they (the children) asked us for food, we gave them these toys to play with, and these made them forgetful till they completed their fast."
وَحَدَّثَنَاهُ يَحْيَى بْنُ يَحْيَى، حَدَّثَنَا أَبُو مَعْشَرٍ الْعَطَّارُ، عَنْ خَالِدِ بْنِ ذَكْوَانَ، قَالَ سَأَلْتُ الرُّبَيِّعَ بِنْتَ مُعَوِّذٍ عَنْ صَوْمِ، عَاشُورَاءَ قَالَتْ بَعَثَ رَسُولُ اللَّهِ صلى الله عليه وسلم رُسُلَهُ فِي قُرَى الأَنْصَارِ ‏.‏ فَذَكَرَ بِمِثْلِ حَدِيثِ بِشْرٍ غَيْرَ أَنَّهُ قَالَ وَنَصْنَعُ لَهُمُ اللُّعْبَةَ مِنَ الْعِهْنِ فَنَذْهَبُ بِهِ مَعَنَا فَإِذَا سَأَلُونَا الطَّعَامَ أَعْطَيْنَاهُمُ اللُّعْبَةَ تُلْهِيهِمْ حَتَّى يُتِمُّوا صَوْمَهُمْ ‏.‏
Reference : Sahih Muslim 1136b
In-book reference : Book 13, Hadith 176
USC-MSA web (English) reference : Book 6, Hadith 2532
  (deprecated numbering scheme)