Genesis 15:1-21
Abram falls into a deep sleep while a smoking firepot and a flaming torch pass alone between the halved animals. The covenant is cut without his participation. One verse later, Yahweh reckons his faith as righteousness — a half-verse Paul will quote four times in Romans 4 alone. Gen 15 is the locus of the unilateral covenant, the chapter where God himself walks under the self-curse, and the OT verse from which the New Testament builds its entire grammar of grace.
Genesis 14:1-24
Melchizedek steps out of nowhere with bread and wine. Two verses, ten Hebrew words, and the entire NT priesthood walks back through him. Gen 14 is the locus of three canonical firsts (kohen, ma-aser, El Elyon as divine title), the chapter where Abram refuses Sodom under oath, and the only OT verse outside Psalm 110 to name Melchizedek. Hebrews quotes him nine times. One sworn divine oath, nine NT citations, seven chapters of argument: the canonical ratio is the argument.