Deuteronomy 21:17
But he shall know the son of the hated for his firstborn, that he give him double of all that he hath. For he is the first of his strength, and to him belongeth the right of the firstbornship.
Genesis 49:3
"Reuben, thou art mine eldest son, my might and the beginning of my strength, chief in receiving and chief in power.
Genesis 25:31-34
And Jacob said, "Sell me this day thy birthright."
Genesis 25:5-6
But Abraham gave all that he had unto Isaac.
1 Chronicles 5:1-2
The sons of Reuben, the eldest son of Israel: for he was the eldest. But because he defied his father's bed, his birthright was given unto the sons of Joseph, the son of Israel, and so he is not reckoned unto the birthright.
Psalm 105:36
He smote all the firstborn in their land, even the chief of all their strength.