The Messenger of Allah ﷺ said, "Whoever is killed defending his property is a martyr, whoever is killed defending his family is a martyr, whoever is killed defending his religion is a martyr, and whoever is killed defending his life is a martyr."
حدثنا سليمان بن داود الهاشمي حدثنا إبراهيم بن سعد عن أبيه عن أبي عبيدة بن محمد بن عمار بن ياسر عن طلحة بن عبد الله بن عوف
قال رسول الله ﷺ من قتل دون ماله فهو شهيد ومن قتل دون أهله فهو شهيد ومن قتل دون دينه فهو شهيد ومن قتل دون دمه فهو شهيد
Its isnad is sahih. Abu Ubayda bin Muhammad bin Ammar bin Yasir is trustworthy, Ibn Main deemed him trustworthy, and it will come at 7038 that Abdullah bin Ahmad also deems him trustworthy. See 1642, 1649, and the following hadith.