The Holy Qur’an.. the Holiest of the book revered by Muslims all over the world. It is the word of Allah (Subhana Wa Ta’la) himself. A word which was sent to Prophet Muhammed (Peach Be Upon Him) through Hazrat Jibril (Gabriel) – Allah’s Arc Angel.
Everytime Allah (SWT) wanted to send a verse of the Qur’an to his followers, Hazrat Jibril would take Allah’s message and produce it verbatim to Allah’s Messenger, Prophet Muhammed (PBUH). And Prophet Muhammed (PBUH) would recite the word of Allah to his companions who would memorize it and also write down and create a written record of the word of Allah.
This did not happen overnight, but the Holy Qur’an was revealed over a period of time. So there was no particular sequential organisation of the various chapters – 114 in all – in the Holy Book. It was upto Prophet Muhammed (PBUH) and his companions to arranged the chapters in Holy Qur’an.
Hence the chapters were arranged according to the number of verses contained barring the first chapter of Al-Fateha, which literally means the begining. So Ch. 2 through Ch. 114 are roughly arranged according to the number of verses starting from the chapter containing most number of verses to the chapter containing least number of verses.
The organization of ayat and Surah and their order is revealed by Allah to His Prophet. Scholars after the Prophet have done additional division of the Qur’an for the convenience of recitation of the whole Qur’an in a set period like one week, one month or two months and so on.
Manazil (stations): The Qur’an is divided into seven approximately equal parts for the convenience of reciting the whole Qur’an in one week. Each of the seven parts is called “Manzil” or station or the plural is Manazil or stations. There is some indication that Prophet Muhammad may have suggested such a division but there is no definite proof of it. A Manzil (singular of Manazil) consists of a number of whole Surahs as given below. If we take Surah 1 as preface of the Qur’an and exclude it from the seven Manazil, the division of Manazil follows:
Manzil No. 1. Surahs 2, 3 and 4.
Manzil No. 2. Surahs 5 to 9.
Manzil No. 3. Surahs 10 to 16.
Manzil No. 4. Surahs 17 to 25.
Manzil No. 5. Surahs 26 to 36.
Manzil No. 6. Surahs 37 to 49.
Manzil No. 7. Surahs 50 to 114.
Juz (Part): In South Asia, Juz is also called “Para”. The Qur’an was equally divided into thirty parts, perhaps based on the number of pages disregarding content or Surah. This was done for the convenience of reciting the whole Qur’an in thirty days or one month. Each Juz is also divided into four quarters or four “ruba”. The Qur’an copies printed anywhere in the world have Juz and quarter markings as ruba’ (first quarter), nusf (one-half) and al-thulatha (three-quarter). This gives 120 quarter-parts of the Qur’an giving the flexibility of reciting the whole Qur’an in equal parts in 30, 60 or 120 days. This type of partitioning of the Qur’an is used very much in South Asia whereas the Arab world does not make much use of it. Even referring to Qur’anic verses South Asians would talk in terms of “Para” number as they carry numbers from 1 to 30 for each Juz. This kind of referring to the Qur’an verses is very unscientific because it does not provide precise location of the verse. If someone says that a verse is in 15th Para, it is not precise enough to find it easily.
Hizb (group): According to this system each Juz is further divided into two Hizbs and each Hizb is further divided into four quarters. It means that a Juz has two Hizbs and eight Hizb-quarters or each Juz-quarter has two Hizb-quarters. The whole Qur’an is divided into 240 Hizb-quarters. This allows a person to recite the Qur’an in small groups of verses and complete the recitation in one-month to eight-month period. In addition, Hizb partitioning of the Qur’an allows a Muqri (Qur’an reciter) to recite one Hizb in each Raka’ah of Salat at-Traweeh and finish one Juz every night in eight Raka’hs thereby completing the whole Qur’an in 30 nights of Ramadan. Partitioning of the Qur’an in Hizb is not found in the copies printed in South Asia.
Ruku’ (bowing or section): Some Muslims prefer to do 20 raka’ah every night for Salat At-Taraweeh during the month of Ramadan, that is, recite a section and go to ruku’ (bowing). They had to find markers to recite a portion of the Qur’an in each Raka’ah while completing a topic. In South Asia the tradition is to complete recitation of the whole Qur’an in 27 nights. This required partitioning of the Qur’an in 27 x 20 = 540 sections excepting the Surah al-Fatiha. When such partitioning was done they ended up with 556 (+1 for Surat al-Fatiha) sections. Evidently, they did not go back to redo the partitioning to come with 540 sections. The Qur’an copies printed in South Asia have Ruku’ or Section markings showing number of the ruku’ within the Surah, within the Juz and ayah number within the ruku’. Traditionally, South Asian Muslims may give reference of a ayahs from the Qur’an by referring to the ruku’ number and Juz number but such system is unscientific and it is not universally acceptable. Qur’an copies printed in the Arab world do not include ruku’ markings.
Groups of Surahs: Some Qur’an scholars talk in terms of groups of Surah or complementary couples of Surahs. These complementary groups or couples are based on the themes and like contents. For example, there is a group of Musabbihat, five Surahs that begin with glorification of Allah (Sabbah lillahi or Yusabbihu lillahi). There are many other groups of Surahs that have been suggested. Also, there are twins or complementary couples, such as Surahs 2 and 3 make a couple, Surahs 91 and 92 is another couple. According to such scholars most of the Qur’an consists of complementary couples.
Source: http://www.ilaam.net/PDF/QuranOrg.pdf