Genesis 49:3,4
Reuben, you are my firstborn, my might, and the beginning of my strength, the excellency of dignity, and the excellency of power:
Nave's Topical Index—AKJV

1 Chronicles 5:1,2
Now the sons of Reuben the firstborn of Israel, (for he was the firstborn; but for as much as he defiled his father's bed, his birthright was given to the sons of Joseph the son of Israel: and the genealogy is not to be reckoned after the birthright.
Nave's Topical Index—AKJV