Deuteronomy 21:17
but he shall acknowledge the firstborn, the son of the hated, by giving him a double portion of all that he has; for he is the beginning of his strength; the right of the firstborn is his.
Genesis 49:3
"Reuben, you are my firstborn, my might, and the beginning of my strength; excelling in dignity, and excelling in power.
Genesis 25:31-34
Jacob said, "First, sell me your birthright."
Genesis 25:5-6
Abraham gave all that he had to Isaac,
1 Chronicles 5:1-2
The sons of Reuben the firstborn of Israel (for he was the firstborn; but, because he defiled his father's couch, his birthright was given to the sons of Joseph the son of Israel; and the genealogy is not to be reckoned after the birthright.
Psalm 105:36
He struck also all the firstborn in their land, the first fruits of all their manhood.