Exodus 13:15

15 For when Pharao was hardened, and would not let us go, the Lord slew every firstborn in the land of Egypt, from the firstborn of man to the firstborn of beasts: therefore I sacrifice to the Lord all that openeth the womb of the male sex, and all the firstborn of my sons I redeem.

Exodus 13:15 Meaning and Commentary

Exodus 13:15

And it came to pass, when Pharaoh would hardly let us go
Showed great reluctance to it, and with difficulty was prevailed upon to dismiss them: that the Lord slew all the firstborn in the land of Egypt, both the
firstborn of men, and the firstborn of beast:
which he did in one night, making use of a destroying angel or angels for that purpose: therefore I sacrifice to the Lord all that openeth thee matrix, being
males;
that is, the firstborn of all clean creatures, as oxen, sheep, and goats: but all the firstborn of my children I redeem;
by paying five shekels apiece to the priest for them, as before observed; and this law continues to be observed with the Jews; the manner of which, as related by Leo Modena F9, is as follows,

``Thirty days being expired after the birth of the child, they call a priest to them; that is to say, one that is descended of the stock of Aaron, whom the father of the child pleaseth; and so, many people being gathered together at the time appointed, the father of the child bringeth before the priest, in a bowl or basin, a good quantity of gold and silver, and then they give him the child into his arms; the priest then calling the mother of it before him, saith unto her, mistress, is this your son? she answereth, yes; then, replies he, have you never had any child before, either male or female, or have miscarried anyone? she saith unto him, no; then doth the priest say, this child is mine, as being the firstborn; then turning himself toward the father, he asketh him, whether he will redeem it or not? who answereth him, saying, see, here is gold and silver, take your own price; then saith the priest unto him, you will redeem it then? the father answereth, I will redeem it; it shall be so then, saith the priest, this child is mine as being the firstborn, as it is written, ( Numbers 18:16 ) . I therefore take this in exchange and so he takes the sum of two French crowns, or thereabout, as he thinks good, and then delivers the child to his father and mother, and this day they make a feasting day.''
This custom was used in Christ's time, and was observed with respect to him, ( Luke 2:27 ) .
FOOTNOTES:

F9 History of the Jews, par. 4. c. 9. sect. 2.

Exodus 13:15 In-Context

13 The firstborn of an ass thou shalt change for a sheep: and if thou do not redeem it, thou shalt kill it. And every firstborn of men thou shalt redeem with a price.
14 And when thy son shall ask thee to morrow, saying: What is this? thou shalt answer him: With a strong hand did the Lord bring us forth out of the land of Egypt, out of the house of bondage.
15 For when Pharao was hardened, and would not let us go, the Lord slew every firstborn in the land of Egypt, from the firstborn of man to the firstborn of beasts: therefore I sacrifice to the Lord all that openeth the womb of the male sex, and all the firstborn of my sons I redeem.
16 And it shall be as a sign in thy hand, and as a thing hung between thy eyes, for a remembrance: because the Lord hath brought us forth out of Egypt by a strong hand.
17 And when Pharao had sent out the people, the Lord led them not by the way of the land of the Philistines, which is near; thinking lest perhaps they would repent, if they should see wars arise against them, and would return into Egypt.
The Douay-Rheims Bible is in the public domain.