"O Messenger of Allah, why will the believers be tested in their graves except the martyr?" He said: "The flashing of the swords above his head is trial enough."
Sunan an-Nasa'i Book 21, Hadith 236
← Previous Hadith "I was sitting with sulaiman bin Sard and Khalid bin 'Urfutah, and they said that a man had died as a result of abdominal illness. They wanted to attend his funeral, and one of them said to the other: 'Didn't the Messenger of Allah say: Whoever is killed by an abdominal illness, he will not be punished in his grave? The other said: 'Yes.'''

Sunan an-Nasa'i Book 21, Hadith 235 Next Hadith → "The plague, abdominal illness, drowning and dying in childbirth are martyrdom." (One of the narrators) said: Abu 'Uthman narrated this to us several times, and on one occasion he attributed it to the Prophet.

Sunan an-Nasa'i Book 21, Hadith 237