For this reason He took upon Himself the responsibility of...
The holy Prophet (P) explained and elaborated the commandments contained in the holy Qur'an. He fixed the Rak'ats in prayers and what was to be recited in them; he also fixed the taxable amount of money and enjoined the rites to be performed during Hajj. He dealt with details of all other religious obligations.
They fabricated narrations and attributed them to the holy Prophet. This is borne out by one of the sayings of Imam Ali (P) in Nahj al-Balagha. Says he: "During the time of the holy Prophet, some people attributed many lies to him and once (Having come to know of the mischief) he stood up from his seat and addressed the people saying 'whoever attributes lies to me deliberately will find his place in Hell' ".
[^1] The trouble mongers continued this malpractice (of attributing lies) even after the demise of the holy Prophet. This is how the Islamic commands were tinged with various hues and ultimately dissensions arose among the Muslims as a whole. Since Allah had already guaranteed the safeguard and protection of the holy Qur'an against all sons of alterations or changes, these vicious people laid their unholy hands on.
the Hadith of the holy Prophet which are the interpreter and elucidator of the intent and import of holy Qur'an. These people fabricated narrations concerning various topics and attributed them to the holy Prophet.