Being called As-Siddeeq by Hazrat Jibreel (‘alaihis salaam)

Hazrat Abu Hurairah (radhiyallahu ‘anhu) mentions that on the night of the Mi’raaj, Rasulullah (sallallahu ‘alaihi wasallam) said to Hazrat Jibreel (‘alaihis salaam), “O Jibreel! My people will not believe me (regarding the journey of Israa and Mi’raaj).” Hazrat Jibreel (‘alaihis salaam) replied, “Hazrat Abu Bakr (radhiyallahu ‘anhu) will believe you, and he is As-Siddeeq (the most truthful).” (Majma‘uz Zawaa’id #14298/14299)

Hazrat ‘Ali (radhiyallahu ‘anhu) Testifies to Hazrat Abu Bakr (radhiyallahu ‘anhu) being As-Siddeeq

Hazrat Nazzaal bin Sabrah (rahimahullah) reports: On one occasion, we asked Hazrat ‘Ali (radhiyallahu ‘anhu), “Please tell us something regarding Hazrat Abu Bakr (radhiyallahu ‘anhu).” Hazrat ‘Ali (radhiyallahu ‘anhu) replied, “Hazrat Abu Bakr (radhiyallahu ‘anhu) was a man whom Allah Ta‘ala bestowed with the title ‘As-Siddeeq’ (the most truthful) on the tongue of Hazrat Jibreel (‘alaihis salaam), as well as on the tongue of Rasulullah (sallallahu ‘alaihi wasallam). He was the khalifah of Rasulullah (sallallahu ‘alaihi wasallam) in leading the salaah (during the final illness of Rasulullah (sallallahu ‘alaihi wasallam)). Rasulullah (sallallahu ‘alaihi wasallam) was pleased for Hazrat Abu Bakr (radhiyallahu ‘anhu) to lead us in our deen, so we are pleased for him to lead us in our dunya.” (Taareekh-ul-Khulafaa pg. 103, Mustadrak Haakim #4406)