The Book of Eclipses
16/4. Chapter:
The command to pray when there is a lunar eclipse
Sunan an-Nasai
أَخْبَرَنَا يَعْقُوبُ بْنُ إِبْرَاهِيمَ، قَالَ حَدَّثَنَا يَحْيَى، عَنْ إِسْمَاعِيلَ، قَالَ حَدَّثَنِي قَيْسٌ، عَنْ أَبِي مَسْعُودٍ، قَالَ قَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم " إِنَّ الشَّمْسَ وَالْقَمَرَ لاَ يَنْكَسِفَانِ لِمَوْتِ أَحَدٍ وَلَكِنَّهُمَا آيَتَانِ مِنْ آيَاتِ اللَّهِ عَزَّ وَجَلَّ فَإِذَا رَأَيْتُمُوهُمَا فَصَلُّوا " .
It was narrated that Abu Mas'ud said: "The Messenger of Allah (ﷺ) said: "The sun and the moon do not become eclipsed for the death or birth of anyone, rather they are two of the signs of Allah (SWT), the Mighty and Sublime, so when you see that then pray.'"
Reference : Sunan an-Nasa'i 1462In-book reference : Book 16, Hadith 4English translation : Vol. 2, Book 16, Hadith 1463