Answered by Shaykh Abdurrahman al-Kharsa
Is it permissible for a child to lead the prayer?
Praise be to Allah
Children are Not Obligated to Pray
A child, or what jurists refer to as a “sabī” (a pre-pubescent child), is not religiously obligated to perform the prayer. This means that prayer is not obligatory for them, and they will not be sinful if they do not perform it. The Prophet (peace and blessings of Allah be upon him) said, “The pen has been lifted from three: from the sleeper until he wakes up, from the child until he reaches the age of puberty, and from the insane person until he regains his senses.” (1)
A Child May Not Lead an Adult in Prayer
If a child performs an obligatory prayer, it will be considered a voluntary prayer since they are not religiously obliged to perform it. Therefore, it is not permissible for an adult to follow a child as their imam in prayer, whether it is an obligatory or voluntary prayer. If an adult does so, their prayer will be invalid.
A Child May Lead Other Children in Prayer
As for children, it is permissible for them to lead other children in prayer, as they are considered peers. The Prophet (peace and blessings of Allah be upon him) said, “The imam is a guarantor.” (2) There is no doubt that one can only guarantee something that is below it, not above it. (3)
May Allah guide us and grant us understanding of the rulings of the noble Sharia. May He grant us success in practicing it, for He is the Most Merciful of the merciful.
(1) Reported by Abu Dawood, At-Tirmidhi, and Ahmad with a sound chain of narrators.
(2) Reported by Abu Dawood with a sound chain of narrators.
(3) See: Al-Binya Sharh al-Hidaya 2/344