(106) باب إِثْمِ مَنْ بَاعَ حُرًّا
Narrated Abu Huraira:
The Prophet (ﷺ) said, "Allah says, 'I will be against three persons on the Day of Resurrection: -1. One who makes a covenant in My Name, but he proves treacherous. -2. One who sells a free person (as a slave) and eats the price, -3. And one who employs a laborer and gets the full work done by him but does not pay him his wages.' "
Reference: Sahih al-Bukhari 2227
In-book reference: Book 34, Hadith 174
USC-MSA web (English) reference(deprecated numbering scheme): Vol. 3, Book 34, Hadith 430