Behaalotekha 

בהעלתך

After the spirit of God rested on the seventy elders and they began prophesying adjacent to the Tent of Meeting, two men, Eldad and Meidad, remained in the camp and also began prophesying. It is stated in their regard: “Two men remained.” To what does the term “remained” refer? 

“Two men remained in the camp” (Numbers 11:26). Some say that they remained from the receptacle [from which both of them drew blank notes in the lottery appointing the elders]. This is because the Holy One, Blessed be He, told Moses to choose for himself seventy elders. Moses said: What should I do? The seventy elders will be divided as six each from each tribe and five each from two tribes. What tribe would volunteer to have only five elders selected from them? Moses implemented a solution. He took seventy notes and wrote “elder” on them and he took two blank notes. Moses mixed them and cast them into the receptacle. He said to them: Come and take your notes. To anyone who took a note on which “elder” was written, Moses would say to him: The Omnipresent has already sanctified you. To anyone who took a note on which “elder” was not written, Moses said to him: It is from Heaven, what can I do for you?... Rabbi Shimon says: They remained in the camp so that they would not be selected. When they saw that Moses was choosing elders, they said: We are not worthy of this prominence, so they went and hid. The Omnipresent said to them: You lowered yourselves; I will elevate you beyond them all. Concerning the seventy elders the verse states: “They prophesied but they did not continue” (11:25). This teaches that they prophesied for a time and then stopped. Concerning Eldad and Meidad the verse states: “They prophesied in the camp” (11:26). This teaches that they continued prophesying until the day of their death. <source>(Sifrei Bemidbar, Behaalotekha 95) </source>