Exodus Exodus 4:1-31
Moses fears the people will not believe him; the chapter ends with the words 'the people believed.' Between those poles God names Israel his firstborn son and arms the exodus with a threat that will fall on every Egyptian household.
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.