Eagerness of Hazrat Abu Bakr (radhiyallahu ‘anhu) to purchase and free Hazrat Bilaal (radhiyallahu ‘anhu):
Hazrat Qays (rahimahullah) mentions that Hazrat Abu Bakr (radhiyallahu ‘anhu) had purchased Hazrat Bilaal (radhiyallahu ‘anhu) for five ooqiyah of gold while he was buried and trapped under a boulder. The disbelievers were so frustrated at how staunch Hazrat Bilaal (radhiyallahu ‘anhu) was on Islam that they mentioned to Hazrat Abu Bakr (radhiyallahu ‘anhu), “We would have sold him to you even if you insisted on paying only one ooqiyah.” Hazrat Abu Bakr (radhiyallahu ‘anhu) replied, “I would have purchased him even if you demanded one hundred ooqiyah!”
(Siyar A‘laam Nubalaa’ 3/219)
Nabi (sallallahu ‘alaihi wasallam)’s wish to share in the reward of freeing Hazrat Bilaal (radhiyallahu ‘anhu):
After Hazrat Abu Bakr (radhiyallahu ‘anhu) purchased Hazrat Bilaal (radhiyallahu ‘anhu), he came to Nabi (sallallahu ‘alaihi wasallam) and informed him of the purchase. Nabi (sallallahu ‘alaihi wasallam) asked Hazrat Abu Bakr (radhiyallahu ‘anhu) if he would make him a partner in the ownership of Hazrat Bilaal (radhiyallahu ‘anhu) through allowing him to purchase a share in him. (Nabi (sallallahu ‘alaihi wasallam) desired to share in the ownership of Hazrat Bilaal (radhiyallahu ‘anhu) so that he would also have a share in the reward when they freed him). Hazrat Abu Bakr (radhiyallahu ‘anhu), however, replied that he had already freed Hazrat Bilaal (radhiyallahu ‘anhu).
(Siyar A‘laam Nubalaa’ 3/219)
Amount paid to purchase Hazrat Bilaal (radhiyallahu ‘anhu):
Different amounts have been narrated regarding the price Hazrat Abu Bakr (radhiyallahu ‘anhu) paid for Hazrat Bilaal (radhiyallahu ‘anhu).
Ibnul Atheer (rahimahullah) has mentioned five ooqiyah, seven ooqiyah and nine ooqiyah. (Usdul Ghaabah 1/237)
‘Allaamah Zahabi (rahimahullah) has quoted a narration of Sha‘bee (rahimahullah) which mentions that Hazrat Abu Bakr (radhiyallahu ‘anhu) had paid forty ooqiyah. (Siyar A‘laam Nubalaa’ 3/219)
Haafiz ibn Hajar ‘Asqalaani (rahimahullah) has mentioned that Hazrat Abu Bakr (radhiyallahu ‘anhu) had paid for Hazrat Bilaal (radhiyallahu ‘anhu) with his own black slave. (Isaabah 1/456)
Killing Umayyah bin Khalaf:
Umayyah bin Khalaf was one of the chief people responsible for torturing Hazrat Bilaal (radhiyallahu ‘anhu). Allah Ta‘ala made it such that Hazrat Bilaal (radhiyallahu ‘anhu) himself killed him in the Battle of Badr. (Usdul Ghaabah 1/237)