Praise be to Allah.
It was proven that the Messenger of Allaah (blessings and peace of Allaah be upon him) said: “This Qur’aan has been revealed in seven styles, so recite whichever is easiest.” And the scholars said: they are close in meaning but different in wording.
When ‘Uthmaan (may Allaah be pleased with him) heard of the differences among the people and Hudhayfah (may Allaah be pleased with him) came to him and said “Save the people,” he consulted the Companions who were still alive at this time, such as ‘Ali, Talhah, al-Zubayr and others, and they suggested compiling the Qur’aan in one style, so that the people would not differ. So he compiled it (may Allaah be pleased with him), and he formed a four-man committee for that task, headed by Zayd ibn Thaabit (may Allaah be pleased with him). So they compiled the Qur'aan in one style, and copied it and distributed it to the various regions so that the people could rely on it and so as to put an end to disputes.
With regard to the seven recitations or ten recitations, they are present in what was compiled by ‘Uthmaan, and have to do with adding a letter or omitting a letter, or elongating or shortening a vowel. All of that is included in the one style that ‘Uthmaan (may Allaah be pleased with him) compiled. The intention behind that was to preserve the word of Allaah and protect people from differences that could harm them or cause fitnah among them. Allaah has not enjoined reciting it in the seven styles, rather the Prophet (blessings and peace of Allaah be upon him) said: “Recite whichever is easiest.” So the people’s agreeing upon one style is a good action for which ‘Uthmaan and the Companions (may Allaah be pleased with them) are to be appreciated, because it made things easier for people and prevented a cause of dispute among the Muslims. End quote.