The Unity of Muslims through the Book and the Sunnah:

Allah—exalted is He—sent Muhammad with the Book and with wisdom so that, by their Lord’s permission, he might lead people out of darkness into light, onto the path of the Almighty, the Praiseworthy.

Allah the Most High says: “Allah has certainly shown favor to the believers when He raised up among them a messenger from themselves who recites His verses to them, purifies them, and teaches them the Book and wisdom, although before that they were in clear error.” 1.

He also says: “Remember Allah’s blessing upon you and what He has sent down to you of the Book and of wisdom whereby He admonishes you.” 2.

And He says to the Prophet’s wives: “And remember what is recited in your homes of Allah’s verses and wisdom.” 3.

The one who recited these in their homes was the Messenger of Allah—may peace and blessings be upon him—namely, the Book of Allah and wisdom.

The Book of Allah is the Qur’an, and the wisdom is the words he conveyed—his Sunnah. Muslims, therefore, must learn both.