That We made it a distinctly lucid Qur'an that you may understand.
3
Tafseer
'Abdullāh Ibn 'Abbās / Muḥammad al-Fīrūzabādī
تفسير : (lo! we have appointed it) we have spoken it, i.e. the qur'an (a lecture in arabic) in the arabic usage, hence the oath, (that haply ye may understand) so that you may know what is in the qur'an of the lawful and unlawful, commands and prohibitions.
Jalāl al-Dīn al-Maḥallī
تفسير : lo! we have made it, we have brought the book into existence [as], an arabic qur’ān, in the language of the arabs, that perhaps you, o people of mecca, may understand, [that you may] comprehend its meanings.