Biblical Commentary on the Old Testament, by Carl Friedrich Keil and Franz Delitzsh, [1857-78], at sacred-texts.com
Abram, having returned from Egypt to the south of Canaan with his wife and property uninjured, through the gracious protection of God, proceeded with Lot למסּעיו "according to his journeys" (lit., with the repeated breaking up of his camp, required by a nomad life; on נסע to break up a tent, to remove, see Exo 12:37) into the neighbourhood of Bethel and Ai, where he had previously encamped and built an altar (Gen 12:8), that he might there call upon the name of the Lord again. That ויּקרא (Gen 13:4) is not a continuation of the relative clause, but a resumption of the main sentence, and therefore corresponds with ויּלך (Gen 13:3), "he went...and called upon the name of the Lord there," has been correctly concluded by Delitzsch from the repetition of the subject Abram.
But as Abram was very rich (כּבד, lit., weighty) in possessions (מקנה, cattle and slaves), and Lot also had flocks, and herds, and tents אהלים for אהלים, Ges. 93, 6, 3) for his men, of whom there must have been many therefore, the land did not bear them when dwelling together (נשׁא, masculine at the commencement of the sentence, as is often the case when the verb precedes the subject, vid., Ges. 147), i.e., the land did not furnish space enough for the numerous herd to graze. Consequently disputes arose between the two parties of herdsmen. The difficulty was increased by the fact that the Canaanites and Perizzites were then dwelling in the land, so that the space was very contracted. The Perizzites, who are mentioned here and in Gen 34:30; Jdg 1:4, along with the Canaanites, and who are placed in the other lists of the inhabitants of Canaan among the different Canaanitish tribes (Gen 15:20; Exo 3:8, Exo 3:17, etc.), are not mentioned among the descendants of Canaan (Gen 10:15-17), and may therefore, like the Kenites, Kenizzites, Kadmonites, and Rephaim (Gen 15:19-21), not have been descendants of Ham at all. The common explanation of the name Perizzite as equivalent to פּרזות ארץ ישׁב "inhabitant of the level ground" (Eze 38:11), is at variance not only with the form of the word, the inhabitant of the level ground being called הפּרזי (Deu 3:5), but with the fact of their combination sometimes with the Canaanites, sometimes with the other tribes of Canaan, whose names were derived from their founders. Moreover, to explain the term "Canaanite," as denoting "the civilised inhabitants of towns," or "the trading Phoenicians," is just as arbitrary as if we were to regard the Kenites, Kenizzites, and the other tribes mentioned Gen 15:19. along with the Canaanites, as all alike traders or inhabitants of towns. The origin of the name Perizzite is involved in obscurity, like that of the Kenites and other tribes settled in Canaan that were not descended from Ham. But we may infer from the frequency with which they are mentioned in connection with the Hamitic inhabitants of Canaan, that they were widely dispersed among the latter. Vid., Gen 15:19-21.
To put an end to the strife between their herdsmen, Abram proposed to Lot that they should separate, as strife was unseemly between אחים אנשׁים, men who stood in the relation of brethren, and left him to choose his ground. "If thou to the left, I will turn to the right; and if thou to the right, I will turn to the left." Although Abram was the older, and the leader of the company, he was magnanimous enough to leave the choice to his nephew, who was the younger, in the confident assurance that the Lord would so direct the decision, that His promise would be fulfilled.
Lot chose what was apparently the best portion of the land, the whole district of the Jordan, or the valley on both sides of the Jordan from the Lake of Gennesareth to what was then the vale of Siddim. For previous to the destruction of Sodom and Gomorrah, this whole country was well watered, "as the garden of Jehovah," the garden planted by Jehovah in paradise, and "as Egypt," the land rendered so fertile by the overflowing of the Nile, "in the direction of Zoar." Abram therefore remained in the land of Canaan, whilst Lot settled in the cities of the plain of the Jordan, and tented (pitched his tents) as far as Sodom. In anticipation of the succeeding history (Gen 19), it is mentioned here (Gen 13:13), that the inhabitants of Sodom were very wicked, and sinful before Jehovah.
After Lot's departure, Jehovah repeated to Abram (by a mental, inward assurance, as we may infer from the fact that אמר "said" is not accompanied by ויּרא "he appeared") His promise that He would give the land to him and to his seed in its whole extent, northward, and southward, and eastward, and westward, and would make his seed innumerable like the dust of the earth. From this we may see that the separation of Lot was in accordance with the will of God, as Lot had no share in the promise of God; though God afterwards saved him from destruction for Abram's sake. The possession of the land is promised עולם עד "for ever." The promise of God is unchangeable. As the seed of Abraham was to exist before God for ever, so Canaan was to be its everlasting possession. But this applied not to the lineal posterity of Abram, to his seed according to the flesh, but to the true spiritual seed, which embraced the promise in faith, and held it in a pure believing heart. The promise, therefore, neither precluded the expulsion of the unbelieving seed from the land of Canaan, nor guarantees to existing Jews a return to the earthly Palestine after their conversion to Christ. For as Calvin justly says, "quam terra in saeculum promittitur, non simpliciter notatur perpetuitas; sed quae finem accepit in Christo." Through Christ the promise has been exalted from its temporal form to its true essence; through Him the whole earth becomes Canaan (vid., Gen 17:8). That Abram might appropriate this renewed and now more fully expanded promise, Jehovah directed him to walk through the land in the length of it and the breadth of it. In doing this he came in his "tenting," i.e., his wandering through the land, to Hebron, where he settled by the terebinth of the Amorite Mamre (Gen 14:13), and built an altar to Jehovah. The term ישׁב (set himself, settled down, sat, dwelt) denotes that Abram made this place the central point of his subsequent stay in Canaan (cf. Gen 14:13; Gen 18:1, and Gen 23). On Hebron, see Gen 23:2.