Ubaidullah bin ‘Abdullah bin 'Utbah bin Mas'ood told us that Abu Hurairah said: When the Messenger of Allah ﷺ died and Abu Bakr رضي الله عنه became (caliph) after him, and some of the Arabs apostatized,ʻUmar رضي الله عنه said: O Abu Bakr, how can you fight the people when the Messenger of Allah ﷺ said: `I have been ordered to fight the people until they bear witness that there is no god except Allah. Whoever bears witness that there is no god except Allah has protected his wealth and his life from me, except in cases dictated by Islamic law, and their reckoning will be with Allah`? Abu Bakr رضي الله عنه said: by Allah I shall certainly fight the one who separates prayer and zakah, for zakah is what is due from wealth. By Allah, whoever withholds from me a goat that they used to give (in zakah) to the Messenger of Allah ﷺ, I shall fight them for withholding it. 'Umar said: By Allah, as soon as I realized that Allah had opened the heart of Abu Bakr to fighting, I realized that it was the right thing to do.