Though
the young are not required to fast, it is proper for their guardians
to encourage them to fast so they will become accustomed to it at an
early age. They may fast as long as they are able to and then may
break it. Ar-Rabi`a bint Mu`awiyyah reported: "The Messenger of
Allah sent a man, on the morning of the day of `Ashurah (the
tenth of the month of Muharram), to the residences of the Ansar,
saying: 'Whoever has spent the morning fasting is to complete his
fast. Whoever has not spent this morning fasting should fast for the
remainder of the day.' We fasted after that announcement, as did our
young children. We would go to the mosque and make toys stuffed with
cotton for them to play with. If one of them started crying due to
hunger, we would give them a toy to play with until it was time to
eat." (Recorded by Al-Bukhari and Muslim)