Tafsir of Ar-Rahman 55:4

Ar-Rahman! He has taught the Qur'an. He created man. He taught him Al-Bayan. Al-Hasan said: "Eloquent speech.'' This refers to Allah teaching the Qur'an, that is, teaching the servants how to recite it by making it easy for them to speak and pronounce letters with the various parts of the mouth, such as the alveolar bridge, the tongue and the lips Among Allah's Signs: the Sun, the Moon, the Sky and the Earth Allah said,

الشمس والقمر بحسبان