Numbers 3:12-14 The Voice (VOICE)
Eternal One: 12-13 As you know, all firstborn children of each woman belong to Me. I made that clear when I killed all the Egyptian firstborn but spared Israel and its animals, setting them apart just for Me. But rather than giving all Israel’s firstborn to Me, I accept the Levites as a substitute. They will be Mine. I am the Eternal One.
The Levites as a whole are given into religious service sacrificing the animals and serving in the congregation tent rather than taking all the firstborn males, as was done with the livestock. To have drawn the servants of the Lord from the entire nation would have resulted in great disruption of each of the families and tribes.
14 God formerly gave these instructions to Moses in the wild desert area of Sinai.