'Birthright' in the Bible

Now the sons of Reuben the firstborn of Israel, (for he was the firstborn; but, forasmuch as 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 reckoned after the birthright.

For Judah prevailed above his brethren, and of him came the chief ruler; but the birthright was Joseph's:)