The Messenger of Allah ﷺ reviewed me on the day of Uhud for battle when I was fourteen years old, and he did not permit me to take part. Then he reviewed me on the day of the Trench when I was fifteen years old, and he allowed me to participate.Nafi said, I came to Umar bin Abdul-Aziz, who was the caliph at that time, and I related this hadith to him. He said, "This is indeed the dividing line between a minor and an adult." So he wrote to his governors instructing them to assign a stipend to whoever was fifteen years old, and as for anyone younger than that, they were to be counted among the dependents.
حدثنا محمد بن عبد الله بن نمير حدثنا أبي حدثنا عبيد الله عن نافع
عرضني رسول الله ﷺ يوم أحد في القتال وأنا ابن أربع عشرة سنة فلم يجزني وعرضني يوم الخندق وأنا ابن خمس عشرة سنة فأجازني قال نافع فقدمت على عمر بن عبد العزيز وهو يومئذ خليفة فحدثته هذا الحديث فقال إن هذا لحد بين الصغير والكبير فكتب إلى عماله أن يفرضوا لمن كان ابن خمس عشرة سنة ومن كان دون ذلك فاجعلوه في العيال