According to most authentic traditions in collections of both Sunni and Shi’a, Ahlul-Bayt (People of the House) of the Prophet are one of the two most precious Symbols of Islam after the departure of the
Prophet (S). There are numerous traditions in the collection of both schools that the Prophet (S) has reminded us to stick to these two weighty things (al-Thaqalain), namely Qur’an and Ahlul-Bayt, in order not to go astray after him.
The Messenger of Allah also informed us that these two weights are non-separable and are with each other till the day of Judgment. This requires us that for understanding the interpretation of Qur’an and the Sunnah of the Prophet (S) we should refer to those who are attached to it, namely Ahlul-Bayt.