Mamre
Mamre carries two interlocking senses across the UPDV: a Hebron-set oak-grove that becomes one of Abraham's settled patriarchal sites, and an Amorite man — brother of Eshcol and Aner — whose name attaches to the same grove and whose three-man confederacy stands beside Abram in the rescue of Lot. The place and the person belong to the single Genesis stretch from Abram's settlement after parting from Lot through Jacob's return to Isaac.
The Oaks of Mamre at Hebron
The first naming places Mamre as the oak-grove inside Hebron where Abram pitches his tent and raises an altar after separating from Lot: "And Abram moved his tent, and came and dwelt by the oaks of Mamre, which are in Hebron, and built there an altar to [the Speech of] Yahweh" (Gen 13:18). The locating-phrase is "the oaks of Mamre," the appositional clause "which are in Hebron" fixes the grove inside the patriarchal-city, and the altar-verb dedicates the same spot as a Yahweh-sanctuary. Mamre enters the narrative as an oak-grove residence and an altar-site in one act.
The Amorite Confederate
Mamre is also a man — an Amorite kinsman whose grove gives the place its name and whose brothers stand with him in Abram's rescue of Lot: "And there came one who had escaped, and told Abram the Hebrew: now he stayed by the oaks of Mamre, the Amorite, brother of Eshcol, and brother of Aner; and these were confederate with Abram" (Gen 14:13). The apposition "the Amorite" identifies Mamre as a man of the Canaanite Amorite stock; the kinship-pair names Eshcol and Aner as his brothers; the closing clause binds all three to Abram by formal confederacy. In the same chapter, when Abram refuses any spoil for himself from the king of Sodom, he keeps the brothers' portion intact: "except only that which the young men have eaten, and the portion of the men who went with me, Aner, Eshcol, and Mamre. Let them take their portion" (Gen 14:24). The exclusion-clause carves the three Amorite confederates out of Abram's own oath of refusal — what Abram declines for himself he secures for them.
Visitation in the Heat of the Day
Mamre is the locale of the visitation that dates the promise of Isaac. The chapter opens with the appearance: "And [the Speech of] Yahweh appeared to him by the oaks of Mamre, as he sat in the tent door in the heat of the day" (Gen 18:1). The setting is the same oak-grove of Genesis 13, the posture-clause seats Abraham at his tent door, and the time-phrase fixes the hour at the heat of the day.
The visitation that follows unfolds entirely on the Mamre site. Abraham looks up and sees three men, runs to meet them, bows himself to the earth, and presses hospitality on them: "let now a little water be fetched, and wash your⁺ feet, and rest yourselves under the tree: and I will fetch a morsel of bread, and strengthen your⁺ heart" (Gen 18:4-5). The grove's tree is the resting-shade, the tent is the kitchen ("Quickly prepare three seahs of fine meal, knead it, and make cakes"), and the herd is the meat-source ("Abraham ran to the herd, and fetched a tender and good calf"); butter, milk, and the dressed calf are set before the visitors and Abraham stands by them under the tree while they eat (Gen 18:6-8).
The promise that fixes the date of Isaac's birth is spoken on this Mamre ground: "I will certainly return to you when the season comes around; and, see, Sarah your wife will have a son" (Gen 18:10). When Sarah laughs inside herself at the announcement, the rebuke-question and the re-affirmation come in the same setting: "Is anything too hard for Yahweh? At the set time I will return to you, when the season comes around, and Sarah will have a son" (Gen 18:14). Mamre, the oak-grove and altar-site, becomes the place where the season-tied son-pledge is fastened to Sarah by name.
A Continuing Patriarchal Seat
The grove continues as a patriarchal residence into the next generation. When Jacob returns from Paddan-aram and rejoins his father, the meeting-point is Mamre: "And Jacob came to Isaac his father to Mamre, to Kiriath-arba (the same is Hebron), where Abraham and Isaac sojourned" (Gen 35:27). The destination-phrase routes Jacob to Mamre, the apposition equates the spot with Kiriath-arba and Hebron, and the relative clause records that "Abraham and Isaac sojourned" there — a two-generation tenure on the same Hebron-set ground that Abram first claimed by tent and altar in Genesis 13.