Israel Like Sand and the Counting Done Only When Needed

Rabbi Menahema and Rabbi Bibi and Rabbi Hiyya the Great in the name of Rabbi Eliezer bar Yaakov: Israel are compared to sand. Just as with sand, you make a hollow in it in the evening and in the morning you find it has filled up again, so too all the thousands who were diminished in the days of David were filled up again in the days of Solomon, as it is said, "Judah and Israel were many, as the sand" (1 Kings 4:20). Rabbi Eliezer said in the name of Rabbi Yose ben Zimra: Whenever Israel were counted for a need, they were not diminished; when counted without need, they were diminished. And when were they counted for a need? In the days of Moses. And when were they counted without need? In the days of David. Rabbi Samuel bar Nahmani said in the name of Rabbi Yonatan: "And they shall give every man a ransom for his soul" (Exodus 30:12) — in the days of Moses. "That there be no plague among them when you count them" (Exodus 30:12) — in the days of David.