Enjoining right and forbidding evil one of the things for which Allah revealed books His books, and with it He sent His messengers, and it is an integral part of the way (i.e. the deen). The message of Allah is composed of informative and directive parts. As for the informative, it is Allah informing us about Himself, such as tauhid (theology), or His informing us about His creation, such as the stories of previous peoples and Prophets in which are contained for us lessons, threats and promises. The directive part consists of commands to do, commands not to do, and things left to our choice and discretion.
Thus, it has been mentioned in the hadith that the chapter of the Qur’an which starts out: [Say: He is Allah, the One…] is equal to one third of the Qur’an, because of its including the third of tauhid. The Qur’an consists oftauhid, commands, and historical events.