Yahya bin 'Ammara يحيى بن عمارة بن أبي حسن الأنصاري · The Book of Funerals

"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)"