Hadith 8:1206
Abu Bakr narrated to us, he said: Abd al-A’la narrated to us, from Ubayd Allah ibn Umar, from Nafi’, from Ibn Umar, he said: He used to take his young children for Hajj. Whoever among them was able to perform the stoning (ramy) would perform it, and whoever was not able, he would perform it on their behalf.
حدثنا أبو بكر قال حدثنا عبد الأعلى عن عبيد الله بن عمر عن نافع عن بن عمر قال كان يحج بصبيانه فمن استطاع منهم ان يرمي رمى ومن لم يستطع رمى عنه