Exodus 13:15

And it came to pass, when Pharaoh stubbornly refused to let us go, that Jehovah slew all the firstborn in the land of Egypt, both the firstborn of men and the firstborn of cattle: therefore I sacrifice to Jehovah all that breaketh open the womb being males; and every firstborn of my children I ransom.
Exodus 13:15 from Darby Bible Translation.
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