Salah bin Kaysan al-Madni صالح بن كيسان المدني أبو محمد · The Book of Jihad

"When the Messenger of Allah (ﷺ) died, some of the 'Arabs apostatized. 'Umar said: 'O Abu Bakr, how can you fight the 'Arabs? Abu Bakr said: 'The Messenger of Allah (ﷺ) said: I have been commanded to fight the people until they testify that La ilaha illallah (there is none worthy of worship except Allah) and that I am the Messenger of Allah, and establish prayer and pay Zakah?' By Allah, if they withhold from me a small she-goat that…

"Belief in Allah and Jihad in the cause of Allah, the Mighty and Sublime."