Likewise, His words:

“It is He who made the sun a radiance and the moon a light, and ordained its phases so that you may know the number of years and the reckoning.”

And likewise, His words:

“We made the night and the day two signs. We effaced the sign of the night and made the sign of the day illuminating, so that you may seek bounty from your Lord and know the number of years and the reckoning.”

He thereby makes clear that all reckoning of years and calculation depends upon His ordaining its phases.

Section

There is no doubt about what we have stated: rulings such as fasting Ramadan are tied to the new moons. However, the means of knowing that the crescent has appeared is sighting it, and nothing else. This is established by revelation and reason.

As for revelation, several people informed us, including our teacher, Imam Abū Muhammad ‘Abd al-Rahmān ibn Muhammad al-Maqdisī, Abū al-Ghanā’im al-Muslim ibn ‘Uthmān al-Qaysī, and others. They said: We were informed by Hanbal ibn ‘Abd Allāh, the muezzin, who said: We were informed by Abū al-Qāsim ‘Abd Allāh ibn Muhammad ibn al-Husayn, who said: We were informed by Abū ‘Alī ibn al-Mudhhib, who said: We were informed by Abū Bakr