Allah sent Muhammad (S) with the Truth

the Qur'an their leader. Nothing of it will be left with them except its name, and they will know nothing save its writing and its words. Before that, they will inflict hardships on the virtuous, naming the latter's truthful views about Allah false allegations, and enforcing for virtues the punishment of the vice. Those before you passed away because of the lengthening of their desires and the forgetting of their death, till that promised event befell them about which excuses are turned down, repentance is denied and punishment and retribution is inflicted. O people, he who seeks counsel from Allah secures guidance and he who adopts His word as guide is led “. . towards what is most upright. . ”(17: 9), because Allah's lover feels secure and His opponent feels afraid. It does not behoove one who knows His greatness to assume greatness, but the greatness of those who know His greatness is that they should abase themselves before Him, and the safety for those who know what His power is, lies in submitting to Him. Do not be scared away from the truth like the scaring of the healthy from the scabbed person, or the sound person from the sick. You should know that you will never know guidance unless you know who has abandoned it, you will never abide by the pledges of the Qur'an unless you know who has broken them, and will never cling to it unless you know who has forsaken it. Seek these things from those who own them because they are the life-spring of knowledge and death of ignorance. They are the people whose commands will disclose to you their (extent of) knowledge, their silence will disclose their (capacity of) speaking and their outer appearance will disclose their inner self. They do not go against religion, and do not differ from one other about it, while it is among them a truthful witness and a silent speaker.