John Calvin Commentary Genesis 25:18

"And they dwelt from Havilah unto Shur that is before Egypt, as thou goest toward Assyria. He abode over against all his brethren." — Genesis 25:18 (ASV)

He died in the presence of all his brethren. Most commentators understand this to refer to his death, as if Moses had said that Ishmael's life was shorter than that of his brothers, who long outlived him. But because the word נפל (naphal) is applied to a violent death, and Moses testifies that Ishmael died a natural death, this interpretation cannot be accepted.

The Chaldean Paraphrast suggests that the word “lot” is implied, and derives this meaning: that the lot fell to him, assigning him a dwelling place not far from his brothers. Although I do not differ greatly on this matter, I still think the words should not be distorted in this way. The word נפל (naphal) sometimes signifies to lie down, or to rest, and also to dwell.

Therefore, Moses' simple assertion is that a dwelling place was given to Ishmael opposite his brothers, so that he would indeed be a neighbor to them, yet would have his own distinct boundaries. For I do not doubt that he referred to the divine message in the sixteenth chapter (Genesis 16:1), where, among other things, the angel said to his mother Hagar, He shall remain, or pitch his tents in the presence of his brethren.

Why does he speak this way about Ishmael rather than the others, except that while they migrated towards the eastern region, Ishmael, although the head of a nation and separated from Abraham's sons, still retained his dwelling in their neighborhood?

Meanwhile, God's intention must also be noted: namely, that Ishmael, though living near his brothers, was still placed apart in his own dwelling, so that he would not mix with them, but would dwell in their presence, or opposite them. Moreover, it is quite clear that the prediction is not to be restricted personally to Ishmael.