Abdullah bin Bakr عبد الله بن بكر بن حبيب السهمي · The Book of Fighting [The Prohibition of Bloodshed]

"When the Messenger of Allah , I will fight them for withholding it.' 'Umar said: 'By Allah, as soon as I saw that Allah has expanded the chest of Abu Bakr to fighting, I knew that it was the truth.'"