is the One whose help is sought.

As for the person who sights the crescent moon on his own:

Under this sub-heading he wrote, “The jurists are unanimously agreed that whoever alone sees the crescent for Ramadan must begin the fast.”

I say: That ruling is not absolute; it is subject to detail that Shaykh al-Islam Ibn Taymiyyah clarified in a fatwa (25/114):

“If someone alone sights the crescent for the start of Ramadan, or alone sights the crescent for ending Ramadan, is he required to fast or to break the fast on the basis of his own sighting, or must he refrain from fasting and not break the fast until he is with other people? There are three opinions, corresponding to the three narrations from Ahmad.”

He then enumerated them, and the view that concerns us—the one that agrees with the hadith—is his statement:

“Third: he fasts with the people and breaks the fast with the people, and this is the clearest opinion because of the Prophet’s words: ‘Your fast is the day you all fast, your breaking of the fast is the day you all break, and your sacrifice is the day you all offer sacrifice.’” Reported by al-Tirmidhī, who graded it ḥasan gharīb.

Ibn Taymiyyah continued, “Some scholars have explained this hadith to mean that fasting and breaking the fast are done together with the community, the great mass of people.”

This hadith is authenticated in al-Ṣaḥīḥah 224 and al-Irwāʾ 905 through several chains from Abū Hurayrah; whoever wishes may consult those sources.

Ibn Taymiyyah further said (117), “However, if someone is in a place where there is no one else, then if he sights the crescent he should fast, for there is no other community there.”