Reference: al-Majmoo’ fee Tarjamatil-Muhaddith Hammaad ibn Muhammad al-Ansaaree wa Seeratuhu wa Aqwaalauhu – Volume 2, Quote No.126, Page 493
Shaykh ‘Abdul-Awwal narrates that he heard his father – Shaykh Hammaad ibn Muhammad al-Ansaaree (rahima-hullaah), say:
The Jews have never gathered together in one place except in this [present] time, and this is from [amongst] the signs of the Prophethood [of Muhammad ﷺ].