Sahih Muslim | Book 6 | Chapter 21

Narrated by Salama b. al-Akwa' (Allah be pleased with him)
Salama b. al-Akwa' (Allah be pleased with him) reported that the Messenger of Allah (may peace be upon him) sent a person of the tribe of Aslam on the day of 'Ashura and commanded him to declare to the people to observe fast in case they had not observed it, and to complete fast till evening if they had taken food

Narrated by Rubayyi' daughter of Mu'awwidh b. 'Afra'
Rubayyi' daughter of Mu'awwidh b. 'Afra' said that the Messenger of Allah (may peace be upon him) sent (a person) on the morning of Ashura to the villages of Ansar around Medina (with this message): He who got up in the morning fasting (without eating anything) he should complete his fast, and he who had had his breakfast in the morning, he should complete the rest of the day (without food). The Companions said; We henceforth observed fast on it (on the day of 'Ashura) and, God willing, made our children observe that. We went to the mosque and made toys out of wool for them and when anyone felt hungry and wept for food we gave them these toys till it was the time to break the fast.

Narrated by Khalid b. Dhakwan
Khalid b. Dhakwan reported: I asked Rubayyi' daughter 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.