Hadithcore
Hadith #2117430

Ibn ’Abbas (RAA) narrated that Allah’s Messenger (ﷺ) said:

“When a man’s slave-woman bears him a child she becomes free at his death.” Related by Ibn Majah and Al-Hakim with a weak chain of narrators.

وَعَنْ اِبْنِ عَبَّاسٍ قَالَ: قَالَ رَسُولُ اَللَّهِ ‏- صلى الله عليه وسلم ‏-{ أَيُّمَا أَمَةٍ وَلَدَتْ مِنْ سَيِّدِهَا, فَهِيَ حُرَّةٌ بَعْدَ مَوْتِهِ } أَخْرَجَهُ اِبْنُ مَاجَهْ, وَالْحَاكِمُ بِإِسْنَادٍ ضَعِيف ٍ [1]‏ .‏

References2 variants
Sunnah.com reference
Book 15, Hadith 18
Arabic/English book reference
Book 15, Hadith 1479