Abdullah bin Abi Bakr (r.a.)
Hz. Abdullah was Hz. Abu Bakr's son and Prophet’s brother-in-law. He became a Muslim in the first years of Islam. He was a clever and skilled man. He played an important role in the Migration of the Prophet. The Prophet remained in the Cave of Thawr for three days during the Migration. Hz. Abdullah brought food to them at night and informed them about the news he gathered from the polytheists by walking around them as his father had wanted him to do. His servant, who was herding the sheep, erased the traces of Abdullah.
Hz. Abdullah obtained the merit of being a "muhajir" by migrating from Makkah. He joined the Conquest of Makkah. He participated in the Battle of Hunayn and the Siege of Taif. During the siege, he was wounded by an arrow that hit him. The wound did not heal. In the first year of his father's caliphate, his wound opened. He passed away. His janazah prayer was led by Hz. Abu Bakr.
Hz. Abu Bakr hid the arrow that wounded Abdullah. Afterwards, he showed this arrow to the delegation Thaqif from Madinah who became Muslims and said,
"Do you know this arrow?" Said bin Ubayd said,
"I made this arrow and I sharpened the tip. I put the feather on it and I threw it. "
Hz. Abu Bakr never wanted a person to die as a polytheist and go to Hell. If his son had killed son Said bin Ubayd, Said would have gone to Hell. However, his son, who was killed by Said, attained the rank of martyrdom. For this reason, Hz. Abu Bakr said to Said bin Ubayd,
"This arrow is the arrow that martyred my son. Praise be to Allah, who gave him martyrdom through your hand, and did not kill you through his hand as an unbeliever! His mercy and grace surrounded both of you. "
Hz. Said also was glad that he had not been killed in the battle as a polytheist. He thanked Allah. May Allah be pleased with them! 
Mustadrak, 3: 478; Bayhaqi, Sunan, 9: 98.