Which Pious Caliph had to fight against those who refuse to pay zakat?

Review the verified answer and explanation for this Motorway Police past-paper question on CampusFin.

Which Pious Caliph had to fight against those who refuse to pay zakat? Answer: Hazrat Abu Bakr (RA)

The Pious Caliph who had to fight those who refused to pay zakat was Abu Bakr. After the death of Prophet Muhammad, many tribes renounced Islam and refused to pay zakat, leading Abu Bakr to fight against them in what are known as the Ridda Wars.