Sunan an-Nasa'i 3162
سنن النسائي#3162SahihSahl bin Abi Umamah bin Sahl bin Hunaif narrated from his father, from his grandfather, that the Messenger of Allah (ﷺ) said:"Whoever asks Allah, the mighty and Sublime, sincerely for martyrdom, Allah will cause him to reach the status of the martyrs even of he dies in his bed
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 Muslim
In-book reference: 25:78