I am relating my question to Hashem and Arabs.
Offhand, I thought that Islam claims ties to Yisma'el. If true, I don't know how or why it makes that claim. If it's all Arabs, even non-Muslims, how do we know this claim is true? Is there Biblical, Talmudic or some other Judaic source that proves this?
The Rashi referenced in my answer there says in part:
אלו ערביים השוכנים באהלים במדברות ורועים מקנה כל ימיהם
These are the arabs that dwell in tents in the desert and pasture flocks all their lives.
So Rashi explicitly conflates the two.
Then again, arabs in Rashi's terminology might more mean desert dwellers rather than the modern definition of Arabs meaning a common cultural connection among a heterogeneous group of people that we think of today. Or perhaps Rashi means Arabians (people specifically from the Arabian peninsula).
So in modern terminology, Yishmoel's descendants may be Arabs today, but not all Arabs are descendants of Yishmoel - and given the degree that Islam in the area has pushed converts (by force or financial pressure), I would be surprised if they claimed real literal genetic decent from Yishmoel, rather than some sort of spiritual heritage.
I remember learning in school a Ramban which comments on the episode with Hagar being kicked out; if you want I can look for it and find the exact wording. Anyways, he writes basically that because Sarah kicked her out, this caused that the Arabs will continue to hate and attack us relentlessly until the times of Mashiach.
Also, there are sefarim kedoshim that mention that the very last part of Galut Edom will be Galut Yishmael, in which the Arabs will take over much of the world and try to wipe out the Jews. Interesting how the Arabs are already taking over Europe and we've had fierce wars with them for the past few decades
