Section: The legislated fast is abstaining from things that break the fast, from the rising of the second dawn until sunset. The meaning of this is narrated from Umar and Ibn Abbas, and it is the position of 'Ata and the general body of scholars. It is narrated from Ali, may Allah be pleased with him, that when he prayed the dawn prayer, he said: 'Now, the white thread has become distinct from the black thread.' A similar statement is reported from Ibn Mas'ud. Masruq said: 'They did not consider the dawn [of which you speak] to be your dawn; they only considered the dawn to be that which fills the houses and the roads.' This is the opinion of al-A'mash. Our evidence is the statement of Allah the Almighty: "...until the white thread of dawn becomes distinct to you from the black thread [of night]" (12), meaning the whiteness of the day from the blackness of the night. This is achieved by the rising of the dawn. Ibn 'Abd al-Barr said, regarding the statement of the Prophet (may Allah bless him and grant him peace): "Bilal calls the adhan at night, so eat and drink until Ibn Umm Maktum calls the adhan" (13), that it is evidence that the 'white thread' is the morning, and that the suhur (pre-dawn meal) cannot be except before the dawn. This is a consensus, in which no one has disagreed except al-A'mash alone, so he was irregular (shadh), and no one paid attention to his opinion. The day that is obligatory to fast is from the rising of the dawn until sunset. He said: This is the position of the group of Muslim scholars.

483 - Issue: Abu al-Qasim, may Allah have mercy on him, said: (And when twenty-nine days of Sha'ban have passed, they shall seek the crescent; if the sky is clear, they shall not fast that day.)

The summary of this is that it is recommended for the people to observe the crescent on the night of the thirtieth of Sha'ban and to search for it, in order to exercise caution for their fasting and to remain safe from disagreement. Al-Tirmidhi (1) has narrated from Abu Hurayrah that the Prophet (may Allah bless him and grant him peace) said: "Calculate the crescent of Sha'ban for Ramadan."