Genesis 46:8
"And these are the names of the children of Israel, which came into Egypt, Jacob and his sons: Reuben, Jacob’s firstborn."
Cross References (ranked by relevance)
Deuteronomy 33:6
Let Reuben live, and not die; and let not his men be few.
Numbers 1:5
And these are the names of the men that shall stand with you: of the tribe of Reuben; Elizur the son of Shedeur.
Genesis 29:32
And Leah conceived, and bare a son, and she called his name Reuben: for she said, Surely the LORD hath looked upon my affliction; now therefore my husband will love me.