The Hadith Thaqalayn telling that the Holy Prophet (pbuh) said “I am leaving two weighty things among you, Quran and Ahlulbayt” was already mentioned in Nisai. This hadith is also mentioned in Sahih Muslim with little bit diffence of wordings. This two narrations clearly say that the Holy Prophet make arrangement for his nation that they wont go astray from right path and advised them to behold the Quran and Ahlulbayt who are his progeny and his blood relation. This is an interesting thing that Hadith Thaqalayn which talked about the Ahlulbayt is mentioned in authentic Sunni sources but our Sunni do not know about it they are only being told about “Quran and Sunnah” which is not even mention in their 6 most authentic hadith (Sihah Sitta).
Sayyidina Jabir ibn Abdullah narrated: I observed Allah’s Messenger (SAW) during his Hajj on the day of Arafah, delivering a sermon while he was seated on his she-camel Qaswa. I heard him say, “0 people, I leave behind with you that to which if you stick, you will not go astray-the Book of Allah and my ahlulbayt my progeny”
Imam Tirmidhi graded this as Hassan Hadith, we do have narration like this from Abu Dhar, Abu Saeed, Zaid bin Arqam and Hudhaifa bin Usaid.
Here is another narration
Zaid bin Arqam narrated that the holy Prophet said “I am leaving two things among you, you won’t astray from right path until you are attached with (these two),one of which is greater than the other, that is Allah’s book which is the rope speeded from sky to earth, and second one is my progeny, my Ahlalbait. These two wont be separate from each other until they will see me at the pond of Kauthar, let us see how you treat with them.”
Imam Tirmidhi graded this as Hassan Hadith.