Supplication for one afflicted by a calamity

"Truly, to Allah we belong, and truly to Him we shall return. O Allah, reward me in my affliction and grant me something better in its place."

The opening clause is from the Qur'an (2:156) — prescribed for every affliction. When Umm Salama رضي الله عنها said this supplication after her husband's death, Allah replaced him with the Prophet ﷺ as her husband.

[Qur'an 2:156; Muslim 2127]