The Islamic Laws of Islam decreed that reaching puberty should be the criterion for a person’s competence for religious assignments. When a male person reaches puberty, he becomes competent for religious assignments and obligations as per the laws of Islam, and would be held accountable for all his actions (and sayings), and the same goes for girls when they start experiencing menstruation. In this hadeeth, Narrated Ibn ‘Umar (may Allah be pleased with him) that Allah's Messenger ﷺ called young men to decide whether or not they were fit to take part in the battles yet, and this was before the battle of Uhud, in 3 A.H. Ibn ‘Umar (may Allah be pleased with him) was fourteen years of age at that time, and he ﷺ did not allow him to take part in that battle, for he ﷺ believed that he was still young and unfit to partake in the battles. In 5 A.H., he ﷺ called him again before the battle of the Trench, when he was fifteen years old, and he ﷺ allowed him (to join the battle). Some scholars objected, saying that since the Battle of the Trench took place in 5 A.H., Ibn ‘Umar (may Allah be pleased with him) should have been sixteen years old and not fifteen. In response, it was said that Ibn ‘Umar (may Allah be pleased with him) meant that he had just turned fourteen before the Battle of Uhud, and had already turned fifteen by the Battle of the Trench, and this was(linguistically) correct and commonly acceptable in the Arabic language. Naafi‘, the freed slave of Ibn ‘Umar (may Allah be pleased with him) and the narrator of the hadeeth, said, "I went to ‘Umar ibn ‘Abd Al-‘Azeez, who was the Caliph at that time, and related the above narration to him, and he deduced from it that the age limit between childhood and manhood is fifteen, and accordingly wrote to his governors to give salaries to those who have reached the age of fifteen should they partake in the battles. It is inferred from the hadeeth that a ruler should keenly do what serves the best interests of the ruled, including specifying the age limit for partaking in battles and joining the Muslim army..