When does business transactions become unlawful on the day of Jumu'ah?

الاستفتاء

On the day of Jumu'ah, does trade become unlawful from the first Azan or the second? Please elaborate. The Ghair Muqallideen say that the second Azan is an innovation of Hazrat Uthman (R.A). They say that the second Azan was not done in the time of the messenger of Allah, nor during the caliphate of Abu Bakr and Umar, therefore it is an innovation. What is our answer to this?

الجواب حامدا و مصلیا

The aforementioned claim of the Ghair Muqallideen is based on their ignorance about the meaning of "Bid'ah" and their lack of understanding of the blessed Ahadith. The Messenger of Allah commanded us to follow the actions and traditions of the Khulafa-e-Rashideen, and Hazrat Uthman is undoubtedly amongst them. Hazrat Uthman order for a second Azan to be done in such a period when many of the companions were present, yet none of them objected to his command. In fact, they too understood the need for a second Azan, hence it was unanimously accepted and practiced from their era until this day. Therefore, (since the unanimity of the Ummah is also a source of Islamic Law), it is not correct to deem the second Azan as a Bid'ah/innovation.
Nonetheless, conducting business transactions or doing any such action that deters one from proceeding to the Jumu'ah Salah becomes prohibitively disliked (Makrooh-Tahreemi) after the first Azan. Such actions must be avoided.