Musnad Ahmad 1156:163

Ibn Numayr narrated to us, he said: Sa‘d ibn Sa‘id narrated to us, he said: ‘Umar ibn Kathir informed me, from Ibn Safinah, the freed slave of Umm Salamah, from Umm Salamah, the wife of the Prophet, may Allah bless him and grant him peace, who said: I heard the Messenger of Allah, may Allah bless him and grant him peace, saying: "There is no servant who is afflicted by a calamity and says: 'To Allah we belong and to Him we shall return. O Allah, reward me in my calamity and replace it for me with something better than it,' except that Allah rewards him for his calamity and replaces it for him with something better than it." She said: "When Abu Salamah died, I said: 'Who is better than Abu Salamah, the companion of the Messenger of Allah, may Allah bless him and grant him peace?'" She said: "Then Allah, the Mighty and Majestic, resolved for me, so I said it: 'O Allah, reward me in my calamity and replace it for me with something better than it.'" She said: "Then I married the Messenger of Allah, may Allah bless him and grant him peace."