Musnad Abu Ya'la al-Mawsili 243:81

On the authority of Abu Musa, he said: The sun eclipsed during the time of the Messenger of Allah, may Allah bless him and grant him peace. He stood to pray with the longest standing, bowing, and prostration I have ever seen him perform in a prayer at all. Then he said: "Indeed, these signs that are sent do not occur for the death of anyone nor for his life, but Allah, the Mighty and Majestic, sends them to frighten His servants with them. So if you see anything of them, then hasten to His remembrance, His supplication, and His seeking of forgiveness."