I believe the hardest rule to not break in the Five Pillars of Islam, would be to fast on the Islamic holy month of Ramadan. During Ramadan ( November) Muslims must fast all day long. They are to only eat and drink before the sun rises, and after the sun goes down. This is a practice that every Muslim does during Ramadan. During Ramadan, when youn feel hunger or thirst, they are supposed to think of Allah, the Muslim one God, and ask him for power to keep going. After Ramadan is over, there is a big feast and you can eat all you want, but you are also supposed to give some to the poor and weak as well. Most Muslims start to fast during Ramadan at the age of 12 or 13. Younger children just give up their favorite foods, like candy or soda. In other words Ramadan is pretty much like Lent.