The Qur'ān was revealed to the Prophet PBUH in parts over a period of twenty-three years. Its revelation occured in various ways: at times in (quick) succession and at times after a period of time. The Qur’ān was revealed gradually and not all at once due to a wisdom Allah  mentioned in the noble Qur’ān,

i.e, thus it has been revealed in parts so that We may strengthen your heart, by its division, so that you may understand it fully and memorise it. And He  said:

i.e, it is a Qur’ān which he  revealed in parts, gradually, at intervals, that is, slowly, without haste and with demonstration; He  revealed it in stages, i.e according to incidents. So, in order to strengthen the heart of the Messenger PBUH and so as to recite it to the people slowly without haste, and also in order to reveal it according to the incidents and with answers to the questions, the Qur’ān was revealed gradually and in parts over twenty-three years.

The Qur’ān would be revealed to the Messenger of Allah PBUH and he  would then instruct the people to memorise it, write it down on pieces of leather or a sheet or papyrus, he would also write on the scapula bone, the palm risp or the lukhaf (a thin broad white stone) i.e on the shoulder blades, leaf stalks of date palm and soft stones. When the ayāt would be revealed he would give the order that they be placed in their proper place in the Sura’s. Thus, he used to say, put this ayah in such and such sura after such and such ayah. So they used to put them in their proper place in the Sura. It has been narrated by 'Uthman  that:

It was done in this manner until the whole Qur’ān was revealed and Allah  took his  soul after the revelation of the Qur’ān was complete. That is why the arrangement of the verses of every Sura in the form as it is now in the present script (mushaf) was as determined by the revelation, from the Prophet , transmitted to him  by Jibreel  from Allah . And according to this arrangement the Ummah transmitted the Qur’ān from her Prophet  and there is no difference (ikhtilaf) about this. The order of the ayat in the Sura’s that we observe today is the very form the Messenger of Allah  ordered. And it is the same form as that was written on the shoulder blades (of animals), palm risps & the lukhaf’s (a thin broad white stone) and preserved in the hearts of men. Consequently, the arrangement of verses within the Sura’s is definite that it is determined by the revelation to the Messenger of Allah , from Jibreel , from Allah . As for the arrangement of the Sura’s, certain chapters (Sura’s) were put together according to the Ijtihād of Sahabah . Ahmad and the Sunan compilers have reported a hadīth by Ibn 'Abbas which has been declared sound by Ibn Hibban and al-Hakim, they narrated:

'I (Ibn 'Abbas) said to 'Uthman 'What induced you to position together Sura al-Anfal which is from the mathani (suras with less than 100 ayāt), and Sura al-Baraa'ah when it is from the mi'un (consisting of about 100 ayāt). You have put them together and you did not write between them the line 'bismillah ar-rahman a-rahim' and you have placed them among the seven long (tiwal) Suras. So 'Uthman said:

It has been narrated by Sa'id ibn Jubayr from Ibn 'Abbas (ra) who said that:

And In another narration:

This indicates that the order of the ayat in every Sura was determined by revelation. And since the Prophet  did not elucidate the issue of Sura baraa'ah 'Uthman  added it to al-Anfal according to his own Ijtihād (may Allah be pleased with him). The author of al-Iqna' reported that the Basmala (abbr. for bismillah ar-rahman ar-rahim) for Baraa'ah is present in the mushaf of Ibn Mas'ud . It has been reported that the Sahabah  used to keep copies whose arrangement of Sura’s was different though there were no differences in the verse arrangement. So the mushaf of Ibn Mas'ud  was compiled in a manner different to the mushaf of 'Uthman  in terms of the arrangement of the Sura’s. It began with al-fatiha, then al-baqarah, al-nisa and Aali 'Imran, contrary to the 'Uthmani mushaf whose arrangement is al-fatiha, al-baqarah, Aali 'Imran and then al-nisa. None of them were compiled according to the order of revelation. It is said that the mushaf of 'Ali (ra) was according to the order of revelation, it began with iqra', then al-muddaththir, nun wal qalam, al-muzzammil, tabbat, al-takweer, sabbih, it went on in this manner to the end of the Makkan suras and then to the Medinan Suras. All of this indicates that the Sura arrangement in relation to some Sura’s was arranged according to the Ijtihād of the Sahabah. That is why maintaining the arrangement of Sura’s in recitation in not obligatory whether in reciting the Qur’ān (tilaawah), in the salah, in a lesson or teaching. As evidenced by the fact that the Prophet  read Sura al-Nisa before Aali 'Imran in his night prayer. As for what has been reported about the prohibition of reciting the Qur’ān in reverse order, what was intended was that an ayah in one Sura should not be read in reverse and not the recitation of Sura’s in reverse order.

Jibreel  would recite all of what had been revealed to the Messenger  from the Qur’ān once every year. And in the year in which the Messenger of Allah  died Jibreel  recited the whole of the Qur’ān twice to the Messenger . It has been narrated by 'Aisha  on the authority of Fatimah  that:

It has been narrated about Abu Hurairah (ra) that he said:

Jibreel's presentation of the Qur’ān to the Messenger  every year means that he presented the arrangment of its verses in relation to other verses and the arrangement of its verses in their respective chapters because presenting the book means to present its sentences, words and arrangement. He presented it to him twice in the year in which the Messenger  died. This means that the arrangement of the verses in relation to each other was presented and as well as the arrangment of verses in their respective Sura’s. Similarly, it is possible to understand the hadīth to mean that the Sura arrangment in relation to each other was presented. However, ther are other ahadīth which explicitly mention the arrangment of the verses. They state the arrangment of the verses in relation to each other and the arrangment of verses in their respective chapters:

And

A Sura would end and another Sura would begin as commanded by Allah  through Jibreel . It has been reported that Ibn 'Abbas  said:

All of this definitely indicates that the arrangement of ayat in their Sura’s and the form of the Suras in terms of the number of verses and their places, all of that is determined by Allah . The Ummah transmitted it in this form from her Prophet  and that is proven by tawaatur (recurrent reports). As for the arrangment of the Sura’s in relation to each other, this can be understood by the ahadith discussing the arrangment of the Qur’ān and it can be understood from other ahadith as well. Narrated by Aisha , the mother of the Believers, that a person from Iraq came to her and asked, 'What type of shroud is the best?' 'Aisha said,'May Allah be merciful to you! What does it matter?' He said, 'O mother of the believers! Show me (the copy of) your Qur’ān,' She said,'Why?” He said, “In order to compile and arrange the Qur’ān according to it, for people recite it with its sura’s not in proper order.” 'Aisha said, “What does it matter which part of it you read first? Know that the first thing that was revealed thereof was a Sura from al-Mufassal, and in it was mentioned Paradise and the Fire. When the people embraced Islam, the ayat regarding legal and illegal things were revealed. If the first thing to be revealed was: 'Do not drink alcoholic drinks.' people would have said, 'We will never leave alcoholic drinks,' and if there had been revealed, 'Do not commit illegal sexual intercourse, 'they would have said, 'We will never give up illegal sexual intercourse.' While I was a young girl of playing age, the following verse was revealed in Makkah to Muhammad:

Then 'Aisha took out the copy of the Qur’ān for the man and dictated to him the verses of the Sura’s (in their proper order). This hadīth shows that the Qur’ān had not been put together (in order), in addition to this the different arrangment of mushafs of the Sahabah indicate that the arrangment of Sura’s in relation to each other was done in agreement amongst the Sahabah.