Narrated Amr bin Suhaib: On his father's authority, said that his grandfather reported the Prophet ﷺ said: When one of you marries his female servant to his slave or to his employee, he should not look at her private part below the navel and above the knees. Abu Dawud said: The correct name is Sawwad bin Dawud al-Muzani al-Sairafi (and not Dawud bin Sawwad as mentioned in the chain). The narrator Waki misunderstood it.
Related hadith on this topic
Explanation & Benefits
Shaykh Umar Farooq Saeedi
Benefits and Issues:
The owner has the right to derive sexual benefit from his slave woman, but when he relinquishes his right and marries her off, then it becomes forbidden for him even to look at the private parts specific to her.
Source: Sunan Abu Dawood – Commentary by Shaykh Umar Farooq Saeedi, Page: 4114