Numbers 3:13

because all the first-born belong to me. When I destroyed all the firstborn in the land of Egypt, I consecrated all the first-born in Israel for myself from human beings to livestock. They belong to me, since I am the LORD."

Exodus 13:2

"Consecrate to me every firstborn male. Whatever is the first to open the womb among the Israelis, both of humans and of animals, belongs to me."

Exodus 13:12

you are to dedicate to the LORD everything that first opens the womb. All the firstborn males of your livestock belong to the LORD.

Exodus 13:15

And when Pharaoh stubbornly refused to let us go, the LORD killed every firstborn in the land of Egypt, from the firstborn of humans to the firstborn of animals. Therefore, I sacrifice to the LORD every male that first opens the womb, but I redeem every firstborn of my sons.

Leviticus 27:26

"No person is to consecrate the firstborn, because the firstborn of the animals already belongs to the LORD. Whether ox or goat, it belongs to the LORD.

Exodus 12:29-30

And so at midnight the LORD struck down every firstborn in the land of Egypt, from the firstborn of Pharaoh who sat on his throne to the firstborn of the prisoner who was in the dungeon, and all the firstborn of the livestock.

Exodus 22:29

"You are not to hold back the fullness of your harvest and the outflow of your wine presses. You are to give to me the firstborn of your sons.

Exodus 34:19

"Everything firstborn belongs to me: all the males of your herds, the firstborn of both cattle and sheep.

Numbers 8:16-17

since they've been set apart for me from among the Israelis. I've taken them for myself instead of the first to open the womb every firstborn of the Israelis,

Numbers 18:15

Everything that opens the womb, any living thing that they bring to the LORD whether from human beings or animals are for you. Just be sure that you redeem the firstborn of people and the firstborn of unclean animals.

Ezekiel 44:30

The first portion of all the first fruits of every kind and every offering of any kind is to be for the priests. You are to give the priest the first portion of your grain. As a result a blessing will rest on your household.

Luke 2:23

as it is written in the Law of the Lord, "Every firstborn son is to be designated as holy to the Lord."

Hebrews 12:23

to the assembly of the firstborn who are enrolled in heaven, to a judge who is the God of all, to the spirits of righteous people who have been made perfect,

Treasury of Scripture Knowledge

Summary

Because all the firstborn are mine; for on the day that I smote all the firstborn in the land of Egypt I hallowed unto me all the firstborn in Israel, both man and beast: mine shall they be: I am the LORD.

Bible References

Because

Numbers 8:16
since they've been set apart for me from among the Israelis. I've taken them for myself instead of the first to open the womb every firstborn of the Israelis,
Numbers 18:15
Everything that opens the womb, any living thing that they bring to the LORD whether from human beings or animals are for you. Just be sure that you redeem the firstborn of people and the firstborn of unclean animals.
Exodus 13:2
"Consecrate to me every firstborn male. Whatever is the first to open the womb among the Israelis, both of humans and of animals, belongs to me."
Exodus 22:29
"You are not to hold back the fullness of your harvest and the outflow of your wine presses. You are to give to me the firstborn of your sons.
Exodus 34:19
"Everything firstborn belongs to me: all the males of your herds, the firstborn of both cattle and sheep.
Leviticus 27:26
"No person is to consecrate the firstborn, because the firstborn of the animals already belongs to the LORD. Whether ox or goat, it belongs to the LORD.
Ezekiel 44:30
The first portion of all the first fruits of every kind and every offering of any kind is to be for the priests. You are to give the priest the first portion of your grain. As a result a blessing will rest on your household.
Luke 2:23
as it is written in the Law of the Lord, "Every firstborn son is to be designated as holy to the Lord."
Hebrews 12:23
to the assembly of the firstborn who are enrolled in heaven, to a judge who is the God of all, to the spirits of righteous people who have been made perfect,

On the day

Exodus 12:29
And so at midnight the LORD struck down every firstborn in the land of Egypt, from the firstborn of Pharaoh who sat on his throne to the firstborn of the prisoner who was in the dungeon, and all the firstborn of the livestock.
Exodus 13:15
And when Pharaoh stubbornly refused to let us go, the LORD killed every firstborn in the land of Egypt, from the firstborn of humans to the firstborn of animals. Therefore, I sacrifice to the LORD every male that first opens the womb, but I redeem every firstborn of my sons.

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