Hadith.861 - Imam Jafar ibn Muhammad Al-Sadiq عليه السلام said: "We command our children to pray when they are five years old, so you should instruct your children to pray when they are seven years old. We also command our children to fast when they are seven years old, as much as they can bear of fasting for the day — whether it is until midday, more, or less. If thirst or hunger overwhelms them, they may break their fast so that they can gradually get accustomed to fasting and be able to bear it. So, instruct your children to fast when they are nine years old, as much as they are capable of fasting for the day. If thirst overwhelms them, they may break their fast."