Narrated As-Saburah: The Prophet ﷺ said: Command a boy to pray when he reaches the age of seven years. When he becomes ten years old, then beat him for prayer.
Hadith Referenceسنن ابي داود / كتاب الصلاة / 494
Hadith Gradingالألبانی:حسن صحيح | زبیر علی زئی:إسناده حسن, مشكوة المصابيح (573)