Tafsir of Al-Isra 17:82

{And We send down of the Qur’an...}

It is read both with takhfif (lightening the nun) and tashdid (doubling the nun).

{Of the Qur’an}: The min (of) is for clarification (lil-tabyin), as in His saying: "of the idols" (min al-awthan). Or, it is for partitive purposes (lil-tab'id), meaning: everything that is sent down of the Qur’an is a healing for the believers. They increase in faith through it and rectify their religion by it; its position for them is like the position of medicine for the sick.

It is narrated from the Prophet (peace be upon him): "Whoever does not seek healing through the Qur’an, may Allah not grant him healing."

{And it does not increase the wrongdoers except in loss}: That is, in deficiency, due to their denial of it and their disbelief, as in the Almighty’s saying: "So it increased them in abomination upon their abomination" (At-Tawbah: 125).

{And when We bestow favor upon man, he turns away and distances himself; and when evil touches him, he is ever despairing. Say, "Each works according to his manner, but your Lord is most knowing of who is best guided in way."}