Allaah - the Most High - also said:
"O you who Believe! If you have taqwaa of Allaah, He will give to you a Furqaan (criterion to judge between right and wrong)."[3]

AI-Haafidh Ibn Katheer (d.777H) - rahimahullaah - said:
Ibn 'Abbaas, as-Suddee, 'Ikrimah, ad-Dahhaak, Qataadah and Muqaatil ibn Hayyaan all said about Furqaan "that it means: a way out (from difficulty)." Mujaahid added: "A way out (from difficulty) both in this world and in the Hereafter." In a narration from Ibn 'Abbaas he said it means: salvation; and in another narration from him: being helped. Muhammad ibn Ishaaq said that it means: "a criterion to judge between truth and falsehood." This explanation from Ibn Ishaaq is the most general of what has already preceeded and it is a necessary consequence of it. Since whoever has taqwaa of Allaah by obeying His command and abandoning what He has prohibited, will be given the ability to recognise truth from falsehood. This will be the cause for his salvation, his being helped; and the cause for his worldly affairs being made easier and his happiness on the Day of Judgement. It will also be the cause for his sins to be expiated by Allaah, and his being granted forgiveness and Allaah shielding him from the people. It will likewise be the cause of him being the recipient (if a great reward from Allaah, as He - the Most High - says: 'O you who Believe! Have taqwaa (fear) of Allaah and believe in His Messenger; and He will bestow upon you a double portion of His Mercy and He will provide you with a light by which you will walk.'[4]"[5]

lbn Mas'ood - radiallaahu anhu - said: "Indeed I hold that a person forgets knowledge that he used to know because of sins that he commits."[6]

Wakee' (d.197H) - rahimahullaah - said: "I seek help in memorization by abandoning sin and disobedience."[7]

Maalik (d.179H) said to ash-Shafi’ee when they first met: "Indeed I see that Allaah has placed a light upon your heart so do not extinguish it with the darkness of disobedience and sin."[8]

Imaam ash-Shaaf'ee (d.204H) - rahimahullaah - said:"Whosoever loves that Allaah Should open up his heart for him and grant light to him, then let him abandon speech about that which does not concern him, and abandon sins and turn away from acts of disobedience. Then there will be between him and Allaah a hidden treasure of good actions. So if this is done, then Allaah will open up such knowledge for him, that will pre-occupy him. And indeed in death is the greatest pre-occupation."[9]

Shaykhul- Islaam Ibn Taymiyyah (d .728 H) said: "Allaah - the Most Perfect - has made as a punishment for people's sins, the absence of guidance and beneficial knowledge, as He says: "They say: Our hearts are wrapped-up (and we do not understand). Rather, Allaah has put a seal upon their hearts because of their disbelief."[10] And He said: "They say: Our hearts are wrapped-up (and we do not understand). Rather, Allaah has cursed them for their disbelief. " [11] And He said: "And we shall turn their hearts and their sight away from guidance, as they refused to believe therein for the first time." [12] And Allaah says: "In their hearts is a disease, and Allaah increases their disease." [13] And He says: "So when they turned away, AlIaah turned their hearts away." [14]" [15]

2. al-Hadeed 57:28

3. aI-Anfaal 8:29

4. al-Hadeed 57:28

5. Tafsir Qur’anil Adheem (2/301-302)

6. Related by Wakee’ in oz-Zuhd (no.329) and its isnaad is Saheeh.

7. Related by Ibn Hibbaan in Rawdatul Uqulaa (p.39).

8. A’laam ul-Muwaqqi’een (4/258) uf Ibn al-Qayyim.

9. Related by al-Bayhaqi in Manaaqib ush-Shafi’ee (2/171).

10. an-Nisaa 4:155

11. al-Baqarab 2:88

12. al-An'aam 6:110

13. al-Baqarab 2:10

14. as-Saff 6l :5

15. Majmoo Fataawaa (14/52) of Ibn Taymiyyah