Imām Muslim reports in the introduction to his Saḥīḥ that Yaḥya b. Saʿīd once said to Al-Qāsim b. ʿUbaydillāh:
“Abu Muḥammad! It feels horrible and grave that you should be asked a question about this religion and not have knowledge about it or a way to get out [and not look like you don’t know].” He replied, “And why is that?” Yaḥya replied, “Because you are the son of two great Imāms of Guidance, Abu Bakr and ʿUmar.” Al-Qāsim said, “Even more horrible than this – to those who understand what Allāh has taught us – is that I should say something without knowledge or report a narration from someone who is not reliable.”
Al-Qāsim b. ʿUbaydillāh was the great grandson of Abu Bakr Al-Ṣiddīq on his mother’s side and the great grandson of ʿUmar b. Al-Khaṭṭāb on his father’s side. His grandfather was ʿAbdullāh b. ʿUmar – Allāh be please with them all.