(Ibid. 26) "And there remained two men in the camp": Some say: They (i.e., their ballots) remained in the ballot box. When the Holy One Blessed be He told Moses to select seventy elders, Moses asked himself: What am I to do? I must select six from each (of the tribes) and five from two tribes. Which tribe will consent to only five?
Moses did as follows: He took seventy ballots and wrote on them "elder," and two blank ballots and mixed them (with the others) in the ballot box, and he said to them: Come and take your ballots. Whoever came up with a ballot marked "zaken," was told by Moses: "The L-rd has already selected you," and whoever came up with a blank ballot was told by Moses: It is the will of Heaven — what can I do? Similarly, (Bamidbar 3:96) "And (for) the redemption (money) of the two hundred and seventy-three of the first-born of the children of Israel over and above the (number of the) Levites, etc." Moses said what am I to do now?
Each one (of the Israelite first-born) will say: A Levite has redeemed me! Moses did as follows: He took (22,000) ballots and wrote upon them "Levite," and (273) ballots and wrote upon them "five shekels," placed them in a ballot box and said to them: Come and take your ballots. Whoever came up with a ballot marked "Levite" was told by Moses: "You have already been redeemed," and whoever came up with a ballot marked "five shekalim" was told by Moses: "Go and give your redemption money (to the Cohanim).
R. Shimon says (on Bamidbar 11:26): "They (Eldad and Medad) remained in the camp, for when they saw Moses selecting elders, they said: We are not deserving of this honor, saying which, they went and hid themselves — whereupon the L-rd said to them: You lowered yourselves; I will exalt you above all the others: Of the seventy elders it is written (Ibid. 25) "And they prophesied — but (after that day), they prophesied no more," whereas of Eldad and Medad it is written (Ibid. 27) "They are prophesying in the camp" — until the day of their death. And what were they saying? "Moses will die and Joshua will bring Israel to Eretz Yisrael."