Al-Jundī narrated it in Faḍāʾil al-Madīnah (no. 31 in my copy).

I say: Its narrators are reliable, apart from Abū Bakr ibn ʿAbd Allāh—namely, Ibn Abī Sabrah—who was accused of fabricating hadiths and is therefore unsuitable for corroboration. Yet the hadith is authentically reported from Jābir with the wording: “Whoever frightens the people of Madinah has frightened me in my very being.” Aḥmad narrated it (3/354 and 393) from Zayd ibn Aslam, from him. Its narrators are those of al-Bukhārī and Muslim, except that this Zayd did not hear from Jābir, as Ibn Maʿīn stated.

Aḥmad ibn al-Muhandis narrated it in Ḥadīth ʿĀfiyah wa-Ghayrihi (2132/1), as did Ibn ʿAsākir (16/240/2), through two routes from the nephew of Jābir ibn ʿAbd Allāh, from Jābir, with the same wording. I have not identified Jābir’s nephew. He was corroborated by ʿAbd Allāh ibn Nasṭās, from Jābir. Ibn ʿAsākir also narrated it from Hāshim ibn Hāshim ibn ʿUtbah ibn Abī Waqqāṣ, from him. Al-Nasāʾī declared ʿAbd Allāh ibn Nasṭās reliable, but no one other than this Hāshim narrated from him.

Muḥammad ibn Kulayb narrated it from Maḥmūd and Muḥammad, the two sons of Jābir, who heard Jābir say it, attributing it to the Prophet, except that they said “the Anṣār” in place of “the people of Madinah.” Al-Bukhārī narrated it in al-Tārīkh (1/1/53 and 4/1/404).

I say: Its narrators are reliable, although Muḥammad ibn Jābir has some weakness, as mentioned above. As for his brother Maḥmūd, al-Bukhārī mentioned this hadith in his biographical entry but did not cite any criticism or commendation of him. Ibn Abī Ḥātim said (4/1/291):