The opponents challenge us by saying that the Shia has been repeatedly mentioning in their books about the…

The opponents challenge us by saying that the Shia has been repeatedly mentioning in their books about the thirst of Imam Hussein (PBUH) during the battle, so they write the following phrase on water tanks: "Drink and remember the thirst of Hussein." The question is: Since the Imams, according to the Shia's understanding, have knowledge of the unseen, couldn't Imam Hussein know his need for water during the battle and that he would die of thirst, and thus gather enough water for the battle? Furthermore, doesn't providing water during the battle fall under taking necessary measures? Allah says: "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"