We find the first mention of Israel in Genesis 32:28: “And He said, 'Your name shall no longer be called Jacob, but Israel; for you have struggled with God and with men, and have prevailed.'” God first uses the name “Israel” to identify Jacob, the progenitor of the twelve tribes of Israel.
From this point forward the Bible uses “Jacob” and “Israel” interchangeably, even in the same sentence. Notice Genesis 48:2: “And Jacob was told, 'Look, your son Joseph is coming to you'; and Israel strengthened himself and sat up on the bed.”
Genesis 48 contains the account where Joseph comes to see his sick and dying father and brings along his two sons, Manasseh and Ephraim (verse 1). After recounting God's promise to him, Israel summons the two boys so he can bless them (verse 9). As part of that blessing, Israel says in verse 16, “The Angel who has redeemed me from all evil, bless the lads; let my name be named upon them, and the name of my fathers Abraham and Isaac; and let them grow into a multitude in the midst of the earth” (emphasis ours). God through Jacob places the name Israel on the sons of Joseph, not Judah, giving us our first glimpse of God's view.
The Nation of Israel—Biblical Israel? (Part One)
Other Forerunner Commentary entries containing Genesis 32:28:
2 Kings 16:1-6