Mishkat al-Masabih #1835

Abu Dharr reported God's messenger as saying, “No Muslim will contribute a pair from every class of property he possesses to be devoted to God’s path without all the guards of paradise meeting him and summoning him to receive what they have.” Abu Dharr asked him what the nature of that would be, and he replied, “If they are camels there will be two, and if they are cows there will be two.” Nasa’i transmitted it.