ʿUmar acquired land at Khaybar and asked the Prophet ﷺ; he said: “If you wish, keep its source and give its produce in charity.” So ʿUmar endowed it — not sold, gifted or inherited — its fruits for the poor, kin, freeing slaves, guests and travellers. (al-Bukhārī). ʿUthmān bought the well of Rūmah and endowed it for the Muslims. (al-Bukhārī).
العربية: عن ابن عمر رضي الله عنهما أنّ عمر أصاب أرضًا بخيبر، فقال النبيّ ﷺ: «إن شئتَ حبستَ أصلها وتصدّقتَ بها»، فتصدّق عمر: لا يُباع أصلها ولا يُوهب ولا يُورث. (البخاري).
Support or set up a waqf — property whose returns keep serving people and rewarding you after death.