‘In that day Yahweh made a covenant with Abram “to your seed I have given this land, from the River of Egypt to the Great River, the River Euphrates”; the Kenite and the Kenizzite and the Kadmonite, and the Hittite and the Perizzite and the Rephaim, and the Amorite and the Canaanite and the Girgashite and the Jebusite.'
So the boundaries of the promised land are fixed in a general sense, to be achieved in the day of Solomon. ‘The river of Egypt' may not be the Nile but the Brook of Egypt (1 Kings 8:65), the southernmost boundary of the land (it is in contrast with ‘the great river', while the Nile is as great a river as the Euphrates), probably the Wadi el Arish just below Gaza, which reaches up towards the Gulfs of Suez and Aqaba, thus excluding the absolute desert. But etymologically it would appear to speak of the Nile for a ‘brook' (nahal) is a torrent wadi arising after the rains, while a river (nehar) is a river of more permanence. There is no difficulty with seeing it as the southernmost part of the Nile in a general sense, not necessarily applied too literally. (We do not know how far south tributaries of the Nile came then). Either way the general boundary is clear. The land reaches from Egypt to the Euphrates, two natural boundaries. In inscriptions Sargon II reaches the ‘brook of Egypt' and establishes a governor there to Pharaoh's alarm (see 2 Kings 24:7).
The writer then summarises the inhabitants of the land that is promised. There are ten in number, a number which signifies totality. (Compare the lists of ten patriarchs). This use in this way of a group of ‘ten' may indicate the great age of the narrative. Later it would be reduced to seven.
The Birth of Ishmael and God's Covenant With Him (Genesis 16:1-14).
This chapter is a record of the covenant God makes with Ishmael and the historical background and theophany that seals it. Without the covenant, which would be put in writing on her return to Abram as evidence of Yahweh's covenant with Ishmael, these events would have disappeared into obscurity.