One of the crucial differences between the new covenant and the old is that in the new covenant, the entire covenant community knows the Lord: “For they shall all know me, from the least of them to the greatest” (Jer 31:34; cf. Isa 54:13). Under the Mosaic administration the covenant community was an ethnic entity marked off by circumcision. To answer the question, Who’s in the covenant?, you would point to all the circumcised offspring of Abraham and their families. Those families were part of the covenant community regardless of whether they knew the Lord. And the covenant itself was administrated by prophets, priests, and kings who were to mediate the knowledge of God to the people. Yet now the new covenant partakes of both a new nature and a new structure. The new covenant’s structure is new in that there’s no need for a set of covenant mediators. Through the work of the covenant’s one mediator, Jesus the Messiah (Heb 8:6; 9:15; 12:24; cf. 1 Tim 2:5), and the indwelling Holy Spi...