that the Hajj is performed in its fullest form, by delaying departure from Minā until the third day rather than leaving early with the first departure, and by observing similar recommended practices of Hajj. An individual would not sin by omitting these, but the imam may not omit them, because it is in the interest of all the pilgrims that their Hajj be performed fully and completely. For this reason:

“When Eid and Friday coincided during the lifetime of the Messenger of Allah, may Allah bless him and grant him peace, he attended the Eid prayer, then granted a concession regarding the Friday prayer, saying, ‘We will hold the Friday prayer.’”

According to the well-known position reported from Ahmad, he and other scholars therefore held that the imam must hold the Friday prayer for them, so that those who attend both may attain the full benefit, even though individuals are permitted to leave. There are many similar examples requiring that the completeness of the community’s religion be preserved in its collective affairs concerning times, places and acts—the religion concerning which Allah said:

“This day I have perfected for you your religion, completed My favour upon you, and approved Islam as your religion.”

Thus, whenever the completeness of the community’s religion would be diminished—even by omitting a recommended practice in a way that leads to its abandonment altogether—ensuring its observance becomes a collective obligation, whether upon the leaders or upon others. The completeness and merit attained through sighting the crescent rather than calculation would therefore be lost through reliance on calculation, even if calculation involved no harm.

The second argument is what the hadiths indicate, as in his words, may Allah bless him and grant him peace:

“Do not begin fasting until you see it, and do not end the fast until you see it.”

This is authentically reported from him in the hadith of Ibn ʿUmar. He thus prohibited fasting before sighting it, and ending the fast before