مِشْكَاةُ الْمَصَابِيحِ
Mishkat al-Masabih 1489
Prayer
Prayer at an Eclipse - Section 1
وَعَنْ أَسْمَاءَ بِنْتِ أَبِي بَكْرٍ رَضِيَ اللَّهُ عَنْهُمَا قَالَتْ: لَقَدْ أَمَرَ النَّبِيُّ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ بِالْعَتَاقَةِ فِي كُسُوفِ الشَّمْسِ. رَوَاهُ البُخَارِيّ
Asma’ daughter of Abu Bakr said that during a solar eclipse the Prophet (ﷺ) gave command that slaves should be set free. Bukhari transmitted it.
Mishkat al-Masabih, 1489صَحِيح (الألباني)