The campaign of the four kings swept relentlessly from north to south along the eastern side of the Jordan River, reaching the southern edge of the land. Along the way, they subdued the ancient tribes living in the region, eventually pushing to the edge of the Sinai desert. Among their targets were the Horites, a prominent ancient people living in the area of Mount Seir.
This specific defeat of the Horites was not merely a random casualty of war, but a deliberate act of God's providence. By allowing the four kings to weaken and destroy these early inhabitants, God was preparing the land for the descendants of Esau. Generations later, Esau's family would inherit Mount Seir, easily conquering the remaining Horites and assimilating with them [שד״ל, ביאור יש״ר, מלבי״ם, ביאור שטיינזלץ].
The exact nature of the attack on the Horites offers two distinct pictures. The primary approach among commentators is that the battle simply took place within their home territory of Mount Seir [רש״י, רד״ק, מזרחי, גור אריה, נתינה לגר]. However, an alternative view suggests a more dynamic scene, indicating that the kings struck the Horites while actively climbing the mountain. In this reading, the attacking armies had to fight their way up the steep slopes of Mount Seir to secure their victory [אבן עזרא, רלב״ג, חזקוני].
After defeating the Horites, the kings pushed forward to a distant location near the Egyptian border, an area adjacent to the wilderness where the Israelites would later camp after leaving Egypt [שד״ל, ביאור יש״ר, מלבי״ם]. The landscape of this destination is a matter of discussion. Some understand its name to be the specific, proper title of a plain located in that region [רש״י]. Others suggest the name actually refers to a place defined by strong, towering trees, such as oaks. Because these massive trees were typically planted in wide, open spaces outside of cities, the translation of Onkelos described the area as a plain, focusing on the broad geographical setting where the trees grew rather than a literal translation of the trees themselves [רמב״ן, שד״ל].
Regardless of its exact landscape, there is a general consensus that this final destination was situated immediately next to the wilderness, resting right on the border of the desert [רש״י, חזקוני, נתינה לגר].