Nasai

1558. Commentary:

➊ "He ordered that the fast be broken": This implies that it is not necessary for all people or for every city and town to sight the moon; rather, if some people sight the moon, it is sufficient for others and for people of other cities as well. Apparently, those who sighted the moon were from outside Madinah, otherwise they would have informed you during the night itself. If the sighting of the moon by people outside Madinah is sufficient for the people of Madinah, then the same ruling applies to other cities as well, except in the case where there is such a difference in the horizon (matal‘) that a difference of a day or more in moon sighting is possible. In that case, their reckoning will be separate. It is also understood that whenever the news of the moon sighting is received, it is obligatory to act upon it. In the case of fasting, it becomes obligatory to break the fast. If it is possible to perform the Eid prayer on the same day before midday (zawal), then it should be performed before midday; and if it is not possible to perform the Eid prayer before midday, then the Eid prayer will be performed the next day. Since, in the matter of moon sighting, generally only a difference of one day is possible, therefore, the Eid prayer should not be delayed by more than one day. The ahadith also mention only a difference of one day. In this issue, both Eids are the same.

➋ If, due to rain or darkness, it is not possible to perform the Eid prayer on the actual day, then the same ruling applies.

➌ "To go out for the Eid prayer": The original practice is that the Eid prayer should be performed in an open field outside the populated area, as this displays greater grandeur and magnificence, and this is also one of the objectives of Eid. Some scholars have stated that the reason for this ruling is that the mosque cannot accommodate the entire population, so due to lack of space, people are ordered to go outside. Thus, if there is a mosque and enough open space adjacent to it that all people can comfortably perform the prayer there, then the Eid prayer can also be performed in the mosque, as is done in the Haramain (the Sacred Mosque in Makkah and the Prophet’s Mosque in Madinah). However, it is not necessary that this is the only reason for the aforementioned ruling; therefore, acting upon the Sunnah of the Prophet (sallallahu alayhi wa sallam) is preferable. And Allah knows best.

1:
From this it is understood that for beginning and breaking the fast, sighting of the moon is necessary; mere astronomical calculation is not sufficient. As for the issue of whether the sighting in one region is valid for another region or not, there is a difference of opinion among the scholars. The group that considers it valid says that the addressees of ((Soomoo)) and ((Aftiroo)) are all the Muslims of the world, therefore the sighting in any one region is the sighting for all regions of the world. And those who say that the sighting of one region is not sufficient for another region, their view is that the addressees of this command are only those Muslims who have seen the moon themselves; those regions where the Muslims have not seen the moon are not addressed by this command. Therefore, they say that each region has its own separate sighting, according to which they will decide whether to fast or not. In this regard, there is also a third opinion: that those regions which are close to each other in terms of horizon—that is, there is not much difference in their sunrise and sunset—for those regions, the sighting in one region is sufficient for the other regions.

Benefits and Issues:
Certainty regarding the sighting of the crescent moon of blessed Ramadan is either based on the completion of thirty days of Sha'ban or on the testimony of people that they have seen the crescent, even if it is only a single just (‘adl) Muslim, as will be mentioned in the ahadith of the next chapter.
The same applies at the end of Ramadan as well.
However, the generality of jurists (fuqaha) consider the sighting by just (‘adl) Muslims to be necessary, whereas Abu Thawr, Abu Bakr ibn al-Mundhir, the Zahiri scholars, and in one narration from Imam Hasan from Imam Abu Hanifah rahimahullah, have considered the sighting of even a single Muslim to be sufficient proof.
The preference of Allamah Shawkani rahimahullah also appears to be that, at the time of breaking the fast, the testimony of two men is not established by any authoritative evidence.
It is only in financial matters that two witnesses are required.
But regarding fasting, there is a clear command: begin fasting upon sighting the crescent and break the fast upon sighting the crescent.
And in acts of worship, a solitary report (khabar wahid) is considered reliable.
(Fiqh al-Sunnah by Sayyid Sabiq, “How the month is established”; Nayl al-Awtar, “Chapter: What establishes fasting and breaking the fast of the months”) Furthermore, if the news of the crescent for Eid is received late and it is not possible to gather for Eid, then the Eid prayer should be performed the next day.