Exodus 4:23 "So I said to you, 'Let My son go that he may serve Me'; but you have refused to let him go. Behold, I will kill your son, your firstborn."'"

Exodus 9:6 So the LORD did this thing on the next day, and all the livestock of Egypt died; but of the livestock of the sons of Israel, not one died.

Exodus 11:4 Moses said, "Thus says the LORD, 'About midnight I am going out into the midst of Egypt,

Exodus 11:5 and all the firstborn in the land of Egypt shall die, from the firstborn of the Pharaoh who sits on his throne, even to the firstborn of the slave girl who is behind the millstones; all the firstborn of the cattle as well.

Numbers 8:17 "For every firstborn among the sons of Israel is Mine, among the men and among the animals; on the day that I struck down all the firstborn in the land of Egypt I sanctified them for Myself.

Numbers 33:4 while the Egyptians were burying all their firstborn whom the LORD had struck down among them. The LORD had also executed judgments on their gods.

Psalm 78:51 And smote all the firstborn in Egypt, The first issue of their virility in the tents of Ham.

Psalm 105:36 He also struck down all the firstborn in their land, The first fruits of all their vigor.

Psalm 135:8 He smote the firstborn of Egypt, Both of man and beast.

Psalm 136:10 To Him who smote the Egyptians in their firstborn, For His lovingkindness is everlasting, (NASB ©1995)