Riyad as-Salihin 992

An-Nawwās ibn Sam‘an reported that the Prophet (may Allah's peace and blessings be upon him) said: “On the Day of Resurrection, the Qur'an and its people who acted upon it will be brought forth, preceded by Sūrat al-Baqarah and Sūrat Āl-‘Imrān, arguing on behalf of those who were committed to them.” the Prophet (may Allah's peace and blessings be upon him) restricted the benefit in this Hadīth, reciting the Qur'an to acting upon it because those who read the Qur'an are of two kinds: the first are those who do not implement it nor believe in its statements and descriptions nor apply the rulings contained therein.

On the Day of Judgment, the Qur'an that they recited will argue against them (because they read it yet did not believe it or act upon it). The second kind are those who believe in its statements and descriptions and apply the rulings it contains. Those are whom the Qur'an will argue for them and on their behalf on the Day of Judgment.

This Hadīth is a manifest proof that the most important thing regarding the Qur'an is to act upon it. This is supported by the statement of Allah, the Almighty: {It is a blessed Book which We have revealed to you, that they might reflect upon its verses and that those of understanding would be reminded} [Sūrah Sād: 29]. To “reflect upon its verses” means to understand their meanings; and “that those of understanding would be reminded” means that they implement those verses.

Reflection preceded implementation in the verse because one cannot act upon a verse if he does not understand its meaning. Reflection leads to the acquisition of knowledge, and implementation is a consequence and fruit of the knowledge. The purpose of the revelation of the Qur'an is that Muslims recite it, act upon it, believe in all its statements and descriptions, implement its rulings, act upon its commands, and avoid its prohibitions.

If he does all of this (sincerely), then on the Day of Judgment, the Qur'an will argue on his behalf.