Exodus 12:29

29 And it came to pass at midnight that the Lord smote all the first-born in the land of Egypt, from the first-born of Pharao that sat on the throne, to the first-born of the captive-maid in the dungeon, and the first-born of all cattle.

Exodus 12:29 Meaning and Commentary

Exodus 12:29

And it came to pass, that at midnight the Lord smote all the
firstborn in the land of Egypt
The midnight of the fifteenth of Nisan, as the Targum of Jonathan, when fast asleep, and thoughtless of any danger; and it being at such a time must strike with a greater horror and terror, when sensible of the blow, which might be attended with a great noise, that might awaken the rest: from the firstborn of Pharaoh that sat on his throne;
the heir to his crown, who was to have sat upon his throne, or already did, being taken a partner with him in it: unto the firstborn of the captive that was in the dungeon;
or prison, that was grinding at the mill there, ( Exodus 11:5 ) which was the work and business the prisoners were often put to, as appears from the case of Samson, ( Judges 16:21 ) , and all the firstborn of cattle;
which were left of the other plagues, which had consumed great numbers of them.

Exodus 12:29 In-Context

27 that ye shall say to them, This passover is a sacrifice to the Lord, as he defended the houses of the children of Israel in Egypt, when he smote the Egyptians, but delivered our houses.
28 And the people bowed and worshipped. And the children of Israel departed and did as the Lord commanded Moses and Aaron, so did they.
29 And it came to pass at midnight that the Lord smote all the first-born in the land of Egypt, from the first-born of Pharao that sat on the throne, to the first-born of the captive-maid in the dungeon, and the first-born of all cattle.
30 And Pharao rose up by night, and his servants, and all the Egyptians; and there was a great cry in all the land of Egypt, for there was not a house in which there was not one dead.
31 And Pharao called Moses and Aaron by night, and said to them, Rise and depart from my people, both ye and the children of Israel. Go and serve the Lord your God, even as ye say.

The Brenton translation of the Septuagint is in the public domain.