Training for war and making the proper preparations for meeting the enemy are recommended, because it is part of the enjoined preparation of power (and steeds of war) stated in the ayah that reads (what means): {And prepare against them whatever you are able of power and of steeds of war by which you may terrify the enemy of Allah and your enemy and others besides them whom you do not know [but] whom Allah knows.} [Quran 8:60]. In this hadeeth, AbooHurayrah narrated that ‘Umar ibn Al-Khattaab(may Allah be pleased with them) came into the Prophet’s Mosque once while some Ethiopians were playing in the presence of the Prophet ﷺ. He (may Allah be pleased with him) picked up a stone and hit them with it. On that the Prophetﷺ said, "O ‘Umar! Allow them (to play)." The Prophet ﷺ said so because he believed that their recreational activity was beneficial for Muslims, as it involved training and getting ready for fighting. It is deduced from the hadeeth that whoever acts on his own personal reasoning and commits a mistake, should not be blamed, because the Prophet ﷺ did not rebuke ‘Umar (may Allah be pleased with him) in that incident..