My father told me that Hakim bin Hizam manumitted one-hundred slaves in the Pre-Islamic period of ignorance and slaughtered one-hundred camels (and distributed them in charity). When he embraced Islam he again slaughtered one-hundred camels and manumitted one-hundred slaves. Hakim said, "I asked Allah's Messenger (ﷺ), 'O Allah's Messenger (ﷺ)! What do you think about some good deeds I used to practice in the Pre-Islamic period of ignorance regarding them as deeds of righteousness?' Allah's Apostle said, "You have embraced Islam along with all those good deeds you did."
Sahih al-Bukhari Book 49, Hadith 22
← Previous Hadith Some men of the Ansar asked for the permission of Allah's Messenger (ﷺ) and said, "Allow us to give up the ransom from our nephew Al-`Abbas. The Prophet (ﷺ) said (to them), "Do not leave (even) a Dirham (of his ransom).

Sahih al-Bukhari Book 49, Hadith 21 Next Hadith → When the delegates of the tribe of Hawazin came to the Prophet (ﷺ) and they requested him to return their properties and captives. The Prophet (ﷺ) stood up and said to them, "I have other people with me in this matter (as you see) and the most beloved statement to me is the true one; you may choose either the properties or the prisoners as I have delayed their distribution." The Prophet (ﷺ) had waited for them for more than ten days since his arrival from Ta'if. So, when it became evident to them that the Prophet (ﷺ) was not going to return them except one of the two, they said, "We choose our prisoners." The Prophet got up amongst the people and glorified and praised Allah as He deserved and said, "Then after, these brethren of yours have come to us with repentance, and I see it logical to return them the captives. So, whoever amongst you likes to do that as a favor, then he can do it, and whoever of you likes to stick to his share till we recompense him from the very first war booty which Allah will give us, then he can do so (i.e. give up the present captives)." The people unanimously said, "We do that (return the captives) willingly." The Prophet (ﷺ) said, "We do not know which of you has agreed to it and which have not, so go back and let your leaders forward us your decision." So, all the people then went back and discussed the matter with their leaders who returned and informed the Prophet (ﷺ) that all the people had willingly given their consent to return the captives. This is what has reached us about the captives of Hawazin. Narrated Anas that `Abbas said to the Prophet, "I paid for my ransom and `Aqil's ransom."

Sahih al-Bukhari Book 49, Hadith 23