Webster(i)
16 For they are wholly given to me from among the children of Israel; instead of such as open every womb, even instead of the first-born of all the children of Israel, have I taken them to me.
17 For all the first born of the children of Israel are mine, both man and beast: on the day that I smote every first-born in the land of Egypt I sanctified them for myself.
18 And I have taken the Levites for all the first-born of the children of Israel.
19 And I have given the Levites as a gift to Aaron and to his sons from among the children of Israel, to do the service of the children of Israel in the tabernacle of the congregation, and to make an atonement for the children of Israel: that there may be no plague among the children of Israel, when the children of Israel come nigh to the sanctuary.