That's because He wasn't.
Read Genesis 15. The covenant between God and Abram. being Jewish, I'm sure you understand the ramifications of breaking a covenant. Now--why do you think God made Abram fall asleep and not actually take part in the covenant ceremony?
Christianity says he is, Paul and the author of Hebrews also.
Read Genesis 15
I am not sure what your point is. The covenant was phased in over time with Abram and then Abraham with G-d repeating the promise after different events. Abram fell asleep to see the exile in Egypt. Deut 31 also predicts exile. But G-d never cancels the covenant and the prohets all prophecy the return of the Jewish people to their and restoration of their relationship to G-d. If G-d would have canceled the covenant, there would be no Jews in Israel today.