Good explanation. Thank you.

You're welcome! Fun exercise to revisit. Reminds of a few key details about "who is Israel?" and "Who is Israel's God?"

I'm not aware of those. What are they? Texts?

I do find the "wrestling with God" thing rather odd. The entire relationship between God and the Israelites in the OT is very strange. Chosen, yes, but also punished for being insufferable...

I understand that a part inside of us "wrestles" with the concept of God. But personally, I'm wrestling with the devil, not with God.

Who is Israel?
Israel is not [just] an ethnic group, but the covenant people of God. Originally Jacob, renamed Israel after wrestling with God (Genesis 32:28), his descendants became a physical nation. But in Christ, the true Israel is revealed as it was always promised: those united to Him by faith, both Jew and Gentile (Galatians 3:7, 3:29; Romans 9:6–8). The Church is the Israel of God (Galatians 6:16).
Who is Israel's God?
The God of Israel is Yahweh, the Triune God (Father, Son, and Holy Spirit.) The same God who covenanted with Abraham, who delivered Moses, who ruled as King over David, and then took on flesh in the person of Jesus Christ (John 1:14; Colossians 2:9).
In Regards to Wrestling 
You say you’re wrestling the devil, not God, but anyone who truly seeks God will find themselves wrestled by Christ and by the Devil. Jesus resists the proud, but gives grace to the humble (James 4:6). That struggle is how He breaks us and blesses us because we need to be perfected for our own good. 
The Devil wrestles us to break us and break us into despair. Very different.