Ibn Majah

´It was narrated from ‘Abdullah bin ‘Abdullah bin Jabir bin ‘Atik, from his father, that his grandfather fell sick and the Prophet (ﷺ) came to visit him. One of his family members said:` “We hoped that when he died it would be as a martyr in the cause of Allah.” The Messenger of Allah (ﷺ) said: “In that case the martyrs of my nation would be few. Being killed in the cause of Allah is martyrdom; dying of the plague is martyrdom; when a pregnant woman dies in childbirth that is martyrdom; and dying of drowning, or burning, or of pleurisy, is martyrdom.”

Abu Hurairah (may Allah be pleased with him) reports that the Prophet (peace and blessings of Allah be upon him) asked: "Whom do you consider to be a martyr?" The people replied: "One who is killed in the way of Allah (is a martyr)." He said: "Then very few in my Ummah would be martyrs!" (Then the Prophet, peace be upon him, said: "No, it is not so, rather) one who is killed in the way of Allah is a martyr, one who dies in the way of Allah is also a martyr, one who dies of a stomach disease is a martyr, and one who dies of plague is a martyr." Suhail says: 'Ubaidullah bin Maqsim informed me, who narrates from Abu Salih, that in it there is an additional wording: "And one who drowns and dies is also a martyr."