Sunan an-Nasa'i 1821
سنن النسائي#1821SahihIt was narrated that Anas said:"The Messenger of Allah said: 'None of you should wish for death because of some harm that befalls him. If he must wish for death, let him say: Allahumma ahini ma kanatil-hayatu khairantli wa tawaffani idha kanatil-wafatu khairanli (O Allah, keep me alive so long as life is good for me, and cause me to die when death is good for me)
Scholarly Authentication
We show the most cautious grade (weakest-wins) as the overall label. Individual scholars graded it as follows:
Abu GhuddahSahih
Al-AlbaniSahih
Zubair Ali ZaiSahih - Agreed Upon
In-book reference: 21:4