Sahih al-Bukhari 1054
Book 16: Eclipses · Narrated by Asma
Arabic
حَدَّثَنَا رَبِيعُ بْنُ يَحْيَى، قَالَ حَدَّثَنَا زَائِدَةُ، عَنْ هِشَامٍ، عَنْ فَاطِمَةَ، عَنْ أَسْمَاءَ، قَالَتْ لَقَدْ أَمَرَ النَّبِيُّ صلى الله عليه وسلم بِالْعَتَاقَةِ فِي كُسُوفِ الشَّمْسِ.
English translation
Narrated Asma:No doubt the Prophet (ﷺ) ordered people to manumit slaves during the solar eclipse
Reference: Sahih al-Bukhari 1054, Book of Eclipses. English translation by Dr. Muhammad Muhsin Khan.