Riyad as-Salihin: The Book of Miscellany – Hadith No. 1519 — Sabrah bin Ma’bad Al-Juhani (May Allah be pleased with him) reported: Messenger… (Hadith No. 1519)

Sabrah bin Ma'bad Al-Juhani (May Allah be pleased with him) reported: Messenger of Allah (ﷺ) said, "Teach a boy Salat (the prayer) when he attains the age of seven years, and punish him (if he does not offer it) at ten"..The narration in Abu Dawud is: Messenger of Allah (ﷺ) said, "Order a boy to perform Salat (the prayer) when he is seven years old".

Explanation:

Reference: Riyad as-Salihin, The Book of Miscellany, Hadith No. 1519