What exactly was Abu ‘Uthman referring to when he told Abu Bakrah
ما هذا الذي صنعتم
This was Abu ‘Uthman An-Nahdi (who was a Mukhadram) expressing his disapproval to what Sayyiduna Abu Bakrah’s blood brother Ziyad did;
He (Ziyad) had claimed to be the son of Abu Sufyan, instead of being the son of Abu Bakrah’s father.
For one to claim to be the son of someone other than his known biological father is a major sin.
However, Sayyiduna Abu Bakrah (radiyallahu’anhu) himself also disapproved of what his brother did.
And Allah Ta’ala Knows best,
Answered by: Moulana Muhammad Abasoomar