From Sahih Bukhari (Hadith 6751):
Narrated `Aisha:I bought Barira (a female slave). The Prophet (ﷺ) said (to me), "Buy her as the Wala' is for the manumitted." Once she was given a sheep (in charity). The Prophet (ﷺ) said, "It (the sheep) is a charitable gift for her (Barira) and a gift for us." Al-Hakam said, "Barira's husband was a free man." Ibn `Abbas said, 'When I saw him, he was a slave
Reference: Bukhari 6751