`Umar used to say, "Abu Bakr is our chief, and he manumitted our chief," meaning Bilal.
Sahih al-Bukhari Book 62, Hadith 99
← Previous Hadith A person asked `Abdullah bin `Umar whether a Muslim could kill flies. I heard him saying (in reply). "The people of Iraq are asking about the killing of flies while they themselves murdered the son of the daughter of Allah's Messenger (ﷺ) . The Prophet (ﷺ) said, They (i.e. Hasan and Husain) are my two sweet basils in this world."

Sahih al-Bukhari Book 62, Hadith 98 Next Hadith → Bilal said to Abu Bakr, "If you have bought me for yourself then keep me (for yourself), but if you have bought me for Allah's Sake, then leave me for Allah's Work."

Sahih al-Bukhari Book 62, Hadith 100