(45) باب فِي وَطْءِ السَّبَايَا
Abu Al Darda said "The Apostle of Allaah(ﷺ) was in a battle. He saw a woman who was nearing the time when she was to deliver a child. "He said "Perhaps the master has intercourse with her.". They(the people) said "Yes". He said "I am inclined to invoke a curse on him which will enter his grave with him. How can he make it (the child) an heir when it is not lawful for him? How can he take it into his service when that is not lawful for him?"
Reference: Sunan Abi Dawud 2156
In-book reference: Book 12, Hadith 111
English translation: Book 11, Hadith 2151