Conversation so far:
what was a reform that was made by Umar?
Umar undertook many administrative reforms, establishing an advanced administration for the newly conquered lands, including several new ministries and bureaucracies, and ordered a census of all the Muslim territories.
were there any other reforms by Umar besides administrative reforms?
During Umar's rule, the garrison cities (amsar) of Basra and Kufa were founded or expanded.
what other reforms did Umar make besides administrative reforms and expanding Basra and Kufa?
In 638, Umar extended and renovated the Masjid al-Haram (Grand Mosque) in Mecca and Al-Masjid al-Nabawi (Mosque of the Prophet) in Medina.
was there another reform by Umar besides administrative reforms, expanding the amsar Basra, expanding the amsar Kufa, extending Masjid al-Haram, and renovating Al-masjid al-Nabawi?
Umar also ordered the expulsion to Syria and Iraq of the Christian and Jewish communities of Najran and Khaybar.

Question: was there any opposition to any of his reforms?
Self-contained rewrite: was there any opposition to any of Umar's reforms?