בַּיּ֣וֹם הַה֗וּא כָּרַ֧ת יְהוָ֛ה אֶת־אַבְרָ֖ם בְּרִ֣ית לֵאמֹ֑ר לְזַרְעֲךָ֗ נָתַ֙תִּי֙ אֶת־הָאָ֣רֶץ הַזֹּ֔את מִנְּהַ֣ר מִצְרַ֔יִם עַד־הַנָּהָ֥ר הַגָּדֹ֖ל נְהַר־פְּרָֽת׃
En aquel día hizo SEÑOR un pacto con Abram diciendo: A tu simiente daré esta tierra desde el río de Egipto hasta el río grande, el río Eufrates;
The Midrash of Philo
What is the meaning of the expression, "Behold there was a smoking furnace and torches of fires, which passed through the middle of those divisions?" (Genesis 15:18).
On Mating with the Preliminary Studies
[119] In the same way He promises to wise Abraham that He will work the ruin and complete destruction of just ten nations, neither more nor less, and will give the land of the victims to his descendants (Gen. 15:18–20). Thus everywhere he thinks well to extend the meaning of the ten, to cover both praise and blame, honour and chastisement.
On Dreams
[255] Again God promises wise Abraham a portion of land “from the river of Egypt to the great river Euphrates” (Gen. 15:18), not meaning a section of country, but rather the better part in ourselves. For our body and the passions engendered in it or by it are likened to the river of Egypt, but the soul and what the soul loves to the Euphrates.