Genesis 35:10

35:10 God said to him, “Your name is Jacob, but your name will no longer be called Jacob; Israel will be your name.” So God named him Israel. 1 

Genesis 35:22

35:22 While Israel was living in that land, Reuben had sexual relations with 2  Bilhah, his father’s concubine, and Israel heard about it.

Jacob had twelve sons:

1 tn Heb “and he called his name Israel.” The referent of the pronoun “he” (God) has been specified in the translation for clarity.

sn The name Israel means “God fights” (although some interpret the meaning as “he fights [with] God”). See Gen 32:28.

2 tn Heb “and Reuben went and lay with.” The expression “lay with” is a euphemism for having sexual intercourse.

sn Reuben’s act of having sexual relations with Bilhah probably had other purposes than merely satisfying his sexual desire. By having sex with Bilhah, Reuben (Leah’s oldest son) would have prevented Bilhah from succeeding Rachel as the favorite wife, and by sleeping with his father’s concubine he would also be attempting to take over leadership of the clan – something Absalom foolishly attempted later on in Israel’s history (2 Sam 16:21-22).