Musannaf Ibn Abi Shaybah

Hazrat Abu Huraira (may Allah be pleased with him) narrates that once the Prophet (peace be upon him) asked, "Whom do you consider to be a martyr?" The people replied, "The one who is killed in the way of Allah." He said, "Then very few in my Ummah would be martyrs. The one who gives his life in the way of Allah is also a martyr, the one who dies by falling from his mount in the way of Allah is also a martyr, the one who drowns in the way of Allah is also a martyr, the one who dies of plague in the way of Allah is also a martyr, the one who dies of a stomach illness in the way of Allah is also a martyr, and the one who dies due to a boil in the way of Allah is also a martyr."