Parshas Bo (10:8-9)
וַיּוּשַׁ֞ב אֶת-מֹשֶׁ֤ה וְאֶֽת-אַהֲרֹן֙ אֶל-פַּרְעֹ֔ה וַיֹּ֣אמֶר אֲלֵהֶ֔ם לְכ֥וּ עִבְד֖וּ אֶת-יְהוָ֣ה אֱלֹהֵיכֶ֑ם מִ֥י וָמִ֖י הַהֹלְכִֽים: וַיֹּ֣אמֶר מֹשֶׁ֔ה בִּנְעָרֵ֥ינוּ וּבִזְקֵנֵ֖ינוּ נֵלֵ֑ךְ, כו׳
And Moshe and Aharon were returned to Paroh, and (Paroh) said to them “Go! Serve Hashem your G-d! Exactly who is to go?” And Moshe said “With our youth and our elders we shall go…”
Exactly who is to go?: Said Paroh to Moshe: what is this that you are asking so persistently to leave? Do you plan on entering into Eretz Yisroel? Exactly who is going to enter Eretz Yisroel? Everyone is destined to die in the wilderness except for Yehosua and Kalev! The words: exactly who is to go (מי ומי ההולכים) has the numerical value of (and was thereby a hinting to) Kalev and Bin Nun! (כלב ובן נון)! To that Moshe retorted: With our youth and our elders we shall leave! For the decree was never made against those under 20 years and those over 60 years!