When must a guardian begin teaching a child prayer (Salah)?

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The guardian must teach the child purity (tahara) and prayer when the child reaches seven years of age. This directive is based on the saying of the Prophet, peace be upon him: 'Teach the child prayer at the age of seven and strike him for it at the age of ten.' This hadith is transmitted by Al-Athram, Abu Dawud, and Al-Tirmidhi, who classified it as Hasan (good). The instruction to teach is for familiarization and habituation so that the child does not abandon prayer upon reaching puberty.