We used to take oath to the Messenger of Allah (ﷺ) that we would listen to and obey his orders. He would tell us (to say in the oath): As far as it lies in my power.
Sahih Muslim Book 33, Hadith 132
← Previous Hadith The Messenger of Allah (ﷺ) never touched a woman with his hand. He would only take a vow from her and when he had taken the (verbal) vow, he would say: You may go. I have accepted your fealty.

Sahih Muslim Book 33, Hadith 131 Next Hadith → The Messenger of Allah (ﷺ) inspected me on the battlefield on the Day of Uhud, and I was fourteen years old. He did not allow me (to take part in the fight). He inspected me on the Day of Khandaq-and I was fifteen yearsold, and he permitted me (to fight), Nafi' said: I came to 'Umar b. 'Abd al-'Aziz who was then Caliph, and narrated this tradition to him. He said: Surely, this is the demarcation between a minor and a major. So he wrote to his governors that they should pay subsistence allowance to one who was fifteen years old, but should treat those of lesser age among children.

Sahih Muslim Book 33, Hadith 133