It is narrated from the holy Prophet of Islam (PBUH) who said:

The Divine School of the Quran and Itrah (Ahlul Bayt (AS)) is always victorious and no other school can rival Divine Revelation [1]. This Hadith (narration) clearly emphasizes the two pivotal elements of the Quran; one is the completeness (comprehensiveness) of the holy Quran, and the other one stresses the point that the Quran is the reference. These two elements mean that: Firstly, the holy Quran covers all the needs in respect of the belief, ethics, judicial, jurisprudential (Fiqh) and similar ones. And the second element is that the holy Quran is the authority (reference) for all the religious sources.

[1] Man la Yahdharahul Faqih, Vol. 4, Page 334.

Source: en.shafaqna.com