There is abundant evidence in the Quran and Sunnah for this “great, comprehensive principle.” Scholars have devoted sections of their books to it under the heading “Book of Holding Fast to the Quran and Sunnah,” as al-Bukhārī, al-Baghawī, and others have done. Whoever holds fast to the Quran and Sunnah is among Allah’s God-fearing allies and belongs to His successful party and His victorious army.

The early generations—including Mālik and others—used to say, “The Sunnah is like Noah’s Ark: whoever boards it is saved, and whoever stays behind drowns.” Al-Zuhrī said, “Those of our scholars who came before us used to say: ‘Holding fast to the Sunnah is salvation.’”

Once this is understood, it is clear that the means by which Allah guides those who are astray, directs those who have gone wrong, and accepts the repentance of sinners must be found in the Quran and Sunnah with which Allah sent His Messenger. Otherwise, if what Allah sent with the Messenger—may Allah bless him and grant him peace—were insufficient for this, the religion brought by the Messenger would be deficient and in need of completion.

It should be understood that Allah has commanded righteous deeds, making them either obligatory or recommended, and has forbidden corrupt deeds. When an action involves both benefit and harm, the Lawgiver is wise: if its benefit outweighs its harm, He prescribes it; if its harm outweighs its benefit, He does not prescribe it, but rather forbids it. As the Most High says:

“Fighting has been prescribed for you, though you dislike it. You may dislike something that is good for you and love something that is bad for you. Allah knows, and you do not know.”

The Most High also says: “They ask you