“The redeemed of the Levites” are the 22,000 who were redeemed by means of the Levites. In Num 3:50, the Chethibh הַפִּדְיֹם is the correct reading, and the Keri הַפְּדֻיִם an unnecessary emendation. The number of the first-born and that of the Levites has already been noticed in the introduction to Numbers 1.