Ibn Abbas narrates that the Messenger of Allah (ص) said:
"Ali ibn Abi Talib is (like) the Gate of Hitta (Gate of Repentence that was in Bani-Israel); whoever enters through it is a believer, and whoever exits from it is an unbeliever"
The word “Hitta” has been used twice in the Qur'an: Sura al-Baqarah, verse 58 and Sura al-A'raf, verse 161, and both are about the Bani-Israel. The gate of “Hitta” was the gate through which the Bani-Israelites entered and remained safe. Perhaps the form of simile in the hadith is that it embodies humility before the Eternal Divine Essence and His laws. The same is true of submission to Ali (ع).
Dailami, Firduas Al-Akhbar, V.3, page 90; Munawi, Faiz al-Qadir, V.4, page 469; Muttaki Hindi, Kanz al-Ummal, V. 11, page 603; Ibn Hajar al-Asqalani, Zahr al-Firdaus, V.2, page 315 as per narration of Ibn Omar; Suyuti, Al-Jami' as-Saghir, V.2, page 177; Salehi Shami, Subulul Huda wal Rashad, V.11, page 297.