The fact is that the first verse which was to be revealed was to a mind who was not prepared to receive so he had to be prepared this is why the first words spoken to him were Iqra speak, read recite, you know all these things are covered by word Iqra so he hesitated so if somebody had said Bismillahir Rahmanir Rahim to him he would not know whether he is expected to repeat the words or not so first of all as a first lesson, instead of saying Bismillahir Rahmanir Rahim it was said Iqra, Bismi Rabbikal Lazi Khalaq so Bismillahir Rahmanir Rahim is replaced again by Bismi Rabbikal Lazi Khalaq you recite in the name of that being who has created.
So you are bound to follow him, you are bound to accept his orders that sort of thing is imperative and the reason of that order is also mentioned in this Bismi Rabbikal Lazi Khalaq, because he is your creator so you have to obey, whether you like it or not so when this was revealed then Bismillah of this surah came later on to be placed before this in order of revelation it is not necessary that in order of revelation whichever precedes must precede it is neither necessary about the surahs nor about the verses the verses revealed afterwards which were put in order before those verses which were revealed earlier those verses which were revealed earlier precedence was given over them in many instances to the verses which were revealed later in time so the surahs which were revealed earlier put much behind.
In order of the arrangement of the Holy Quran for instance the last surah, this very surah is in the last chapter, last part of the Holy Quran while it is the first surah so that arrangement of the Holy Quran has nothing to do with the chronology of its revelation the arrangement was made under instructions from Hazrat Jibreel Allah instructed him to help Huzoor-e-Akbar organize the Holy Quran in its permanent position so the order of revelation was different it was to meet the requirements of that time but the permanent order of the Holy Quran was designed to be different which was to stay forever, so this is why there are differences between the time of revelation and the placing of that verse or surah
