It is narrated from Sayyiduna Anas bin Malik (may Allah be pleased with him) that when the Messenger of Allah (peace and blessings be upon him) passed away and the Arabs apostatised (in the matter of zakah), Sayyiduna Umar bin al-Khattab (may Allah be pleased with him) said: O Abu Bakr! Do you intend to fight the Arabs? Sayyiduna Abu Bakr (may Allah be pleased with him) said: The Messenger of Allah (peace and blessings be upon him) said only this: "I have been commanded to fight people until they bear witness that there is no god but Allah and that I am the Messenger of Allah, and they establish the prayer and pay the zakah." So by Allah! If they refuse to give even a young goat which they used to give to the Messenger of Allah (peace and blessings be upon him), I will certainly fight them over it. Sayyiduna Umar (may Allah be pleased with him) says: Then when I saw that Allah had opened the chest of Abu Bakr (may Allah be pleased with him) to this view, I understood that it was the truth. This hadith is sahih al-isnad (with an authentic chain). Although the two Shaykhs did not take the narration of Imran al-Qattan, they have no evidence for abandoning him, for his hadith is sound. A supporting narration (shahid) for it is the hadith of Abu al-Anbas, which the two Shaykhs did not record:

Sayyiduna Abu Hurayrah (may Allah be pleased with him) states that the Messenger of Allah (peace and blessings be upon him) said: "I have been commanded to fight people until they bear witness that there is no god but Allah, and they establish the prayer and pay the zakah. Then their blood and their wealth will be protected from me, and their (inner) reckoning will rest with Allah, the Mighty and Majestic."