Narrated As-Sa'ib ibn Yazid: As-Sa'ib reported on the authority of a man whom he named: The Messenger of Allah ﷺ put on two coats of mail during the battle of Uhud as a double protection. (The narrator is doubtful about the word zahara or labisa)
The hadith also reminds us that we should never underestimate our enemies or think that they are weak or powerless because they can surprise us with their strength and courage if we are not careful enough. We must always be vigilant and alert so as not to fall into any traps set by them. Lastly, it teaches us the importance of being prepared for any situation no matter how difficult it may seem at first glance.