Sheikh Riyâd al-Musaymîrî, professor at al-Imâm University in Riyadh
We appreciate your concern for Allah’s book.
You have said that the Qur’ân was revealed by verses and not by chapters. This is not always true. There are some chapters which were revealed as a whole, such as Sûrah al-Fâtihah, many of the short chapters, Sûrah al-An`âm, and others.
It was related that once the Prophet (peace be upon him) had a nap then woke up smiling.
The Companions asked him: “What has made you smile, O Messenger of Allah?”
He said: “A chapter was just revealed to me: 'To you have We granted the abundance. Therefore to your Lord turn in prayer and sacrifice. For indeed he who hates you will be cut off (from future hope).' ” [Sûrah al-Kawthar]
The arranging of the verses into their chapters was most definitely carried out by the Prophet (peace be upon him) himself and not according to people’s whims and predilections. The Prophet (peace be upon him) used to inform his scribes where to place each verse.
Source: Islam Today