What are the rules of fasting in islam?
One of the five conditions of Islam is to fast in the month of Ramadhan. Fasting, became fardh in the second year of the Hijrah. It is stated in the Qur’an:
Our Prophet stated: ” Islam has been built on five pillars: testifying that there is no deity worthy of worship except Allah and that Muhammad is the Messenger of Allah, establishing the Salaah (prayer), paying the Zakat (obligatory charity), making the Hajj (pilgrimage) and fasting in Ramadhan.”
In order for the Ramadhan fasting to be considered fardh, it must be the time of that month. Rasulullah-peace be upon him- stated:” Start fasting when you see the crescent of the month of Ramadhan.”
As it is understood from the ayahs and hadith, it is fardh for every Muslim who is mukallaf to fast in the month of Ramadhan every year. It is reason for a person to leave the religion when they take the matter of fasting lightly or when they deny that it is fardh. As for the person who believes it is fardh but still does not fast without having an excuse, they will be a sinner.
 Surat Baqarah, Ayah 183
 Surat Baqarah, Ayah 185
 Sahihu’l-Bukhari, Kitabu’l-Iman, c. I. s. 8: Sahihu’l-Muslim, Kitabu’l-Iman. 21.
 Sunanu’t-Tirmidhi, Babu’s-sawm, 683.