The Reason it is called Umm Al-Kitab
In the beginning of the Book of Tafsir, in his Sahih, Al-Bukhari said; "It is
called Umm Al-Kitab, because the Qur'an starts with it and because the prayer is
started by reciting it.'' It was also said that it is called Umm Al-Kitab,
because it contains the meanings of the entire Qur'an. Ibn Jarir said, "The
Arabs call every comprehensive matter that contains several specific areas an
Umm. For instance, they call the skin that surrounds the brain, Umm Ar-Ra's.
They also call the flag that gathers the ranks of the army an Umm.'' He also
said, "Makkah was called Umm Al-Qura, (the Mother of the Villages) because it is
the grandest and the leader of all villages. It was also said that the earth was
made starting from Makkah.''
Further, Imam Ahmad recorded that Abu Hurayrah narrated about Umm Al-Qur'an
that the Prophet said,
«هِيَ أُمُّ
الْقُرْآنِ وَهِيَ السَّبْعُ الْمَثَانِي وَهِيَ الْقُرْآنُ الْعَظِيمُ»
(It is Umm Al-Qur'an, the seven repeated (verses) and the Glorious Qur'an.)
Also, Abu Ja`far, Muhammad bin Jarir At-Tabari recorded Abu Hurayrah saying
that the Messenger of Allah said about Al-Fatihah,
«هِيَ أُمُّ
الْقُرْآنِ وَهِيَ فَاتِحَةُ الْكِتَابِ وَهِيَ السَّبْعُ الْمَثَانِي»
(It is Umm Al-Qur'an, Al-Fatihah of the Book (the Opener of the Qur'an) and
the seven repeated (verses).)