Sahih al-Bukhari 1059
Narrated Abu Musa:
The sun eclipsed and the Prophet (ﷺ) got up, being afraid that it might be the Hour (i.e. Day of Judgment). 
He went to the Mosque and offered the prayer with the longest Qiyam, bowing and prostration that I 
had ever seen him doing. Then he said, "These signs which Allah sends do not occur because of the 
life or death of somebody, but Allah makes His worshipers afraid by them. So when you see anything 
thereof, proceed to remember Allah, invoke Him and ask for His forgiveness."
حَدَّثَنَا مُحَمَّدُ بْنُ الْعَلاَءِ، قَالَ حَدَّثَنَا أَبُو أُسَامَةَ، عَنْ بُرَيْدِ بْنِ عَبْدِ اللَّهِ، عَنْ أَبِي بُرْدَةَ، عَنْ أَبِي مُوسَى، قَالَ خَسَفَتِ الشَّمْسُ، فَقَامَ النَّبِيُّ صلى الله عليه وسلم فَزِعًا، يَخْشَى أَنْ تَكُونَ السَّاعَةُ، فَأَتَى الْمَسْجِدَ، فَصَلَّى بِأَطْوَلِ قِيَامٍ وَرُكُوعٍ وَسُجُودٍ رَأَيْتُهُ قَطُّ يَفْعَلُهُ وَقَالَ ‏
"‏ هَذِهِ الآيَاتُ الَّتِي يُرْسِلُ اللَّهُ لاَ تَكُونُ لِمَوْتِ أَحَدٍ وَلاَ لِحَيَاتِهِ، وَلَكِنْ يُخَوِّفُ اللَّهُ بِهِ عِبَادَهُ، فَإِذَا رَأَيْتُمْ شَيْئًا مِنْ ذَلِكَ فَافْزَعُوا إِلَى ذِكْرِهِ وَدُعَائِهِ وَاسْتِغْفَارِهِ ‏"‏‏.‏