Hadithcore
Musnad Ahmad 1511
da’if· Darussalam

It was narrated that "Abdullah bin ar-Ruqaim al-Kinani said:

We went out to Madinah at the time of the Battle of the Camel, and we met Sa’d bin Malik there, who said: “The Messenger of Allah (ﷺ) instructed us to shut the gates that led from the houses into the mosque, but to leave the gate of "Ali (رضي الله عنه).”

References1 variant
Arabic/English book
Book 8, Hadith 1511