Sahih Muslim – Hadith No : 1938

Ibn ‘Abbas reported Allah’s Messenger (may peace be upon him) as saying: Gabriel taught me to recite in one style. I replied to him and kept asking him to give more (styles), till he reached seven modes (of recitation). Ibn Shibab said: It has reached me that these seven styles are essentially one, not differing about what is permitted and what is forbidden.

Hadith In Arabic Text :

حدثنا إسحاق بن إبراهيم، وعبد بن حميد، قالا أخبرنا عبد الرزاق، أخبرنا معمر، عن الزهري، كرواية يونس بإسناده ‏.‏

Chapter : The Book of Prayer (Travellers) – كتاب صلاة المسافرين وقصرها