What are the reasons for the emergence of the Quranic recitations (Qira'at) and what is the ruling of the فقهاء (jurists) concerning them?

It is not correct to say that the variant readings (Qira'at) emerged; rather, the Qur'an was revealed with them from Allah as a means of alleviation and facilitation for the Ummah, and to demonstrate its eloquence and inimitability, to confirm the truthfulness of the Prophet, peace and blessings be upon him, to indicate the miraculous nature of the Qur'an, to increase the rewards for the Ummah, and to show Allah's preservation of His Book.

Jurists permit recitation with any established reading, and it is permissible to combine them, because the Prophet, peace and blessings be upon him, taught the Companions in various ways, and thus the readings spread through the Companions and their successors (Tabi'in) until they were attributed to the well-known imams of recitation.