Deuteronomy 21:17
But he shall acknowledge the son of the hated as the firstborn, 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, the excellency of dignity, and the excellency of power:
Genesis 25:31-34
And Jacob said, Sell me this day your birthright.
Genesis 25:5-6
And Abraham gave all that he had unto Isaac.
1 Chronicles 5:1-2
Now the sons of Reuben the firstborn of Israel, (for he was the firstborn; but, since he defiled his father's bed, his birthright was given unto the sons of Joseph the son of Israel: and the genealogy is not to be recorded according to the birthright.
Psalm 105:36
He struck also all the firstborn in their land, the first of all their strength.