This Prophetic Hadeeth (Ali in this Ummah is like the Ka'bah) has been narrated in both Shia and Sunni books including:
1. al-Soyooti in his book Thail Al-La'aali , page 62.
2. Tareekh Dimishq by Ibn Asaakir Al-Shafi'ee, V. 42, Page 356 .
3. Al-Manaaqib by Ibn Al-Maghaazili , page 107 and 149.
4. Kifayat Al-Taalib, page 161.
5. al-Manaaqub by ibn Shahrashoob , v.3, page 202.
6. Osd Al-Ghaabah by Ibn Al-Atheer, V. 4, P. 106.
7. al-Manaawi in his book Konooz Al-Haqaa'eq , page 203.
8. Al-Qondoozi Al-Hanafi in Yanabee' Al-Mawaddah, page 182.
and many other Sunni and Shia books.
The Hadeeth means among many important points that people should come to Ali for guidance and following him, and he should never go to any one for guidance or following.
Worshiping Allah in obligatory Prayers is only accepted when you face the Ka'bah, and obeying Allah is only accepted when you follow Ali as the appointed divine leader after the Prophet by order of Allah (SAWA).