What's the foundation?

Accordingly, in the biblical world, covenant was not made just or primarily on the basis of blood. To be a son or daughter was first of all, in Hebrew thought, to be obedient, not to indicate biological descent. Israel’s election as the “children of God” entailed obedience (Deut l3:17–l4:2). If Israel disobeyed, God might spurn “his sons and daughters” (Deut 32:l9—20), sell them into slavery (Isa 50:l), and declare them no longer God’s people (Hos 1:9). It is likely in this spirit, a covenant spirit, that Jesus turned away from his consanguineous mother and siblings and declared instead, “Whoever does the will of God is my brother and sister and mother” (Mark 3:31-35). Jesus’s primary family, in this sense, is composed not of those who share his genetic makeup but of those who share his obedient spirit.

At the same time, such remarks must be kept in tension with an underlying unconditional quality about covenant. Though Israel (and later the church) repeatedly fails and betrays its Lord in what the prophets portray as adulterous liaisons with other gods, Yahweh shows a determination to never give up or turn God’s back on his people. The romance between God and his people is stormy and too often ruptures.— Naming Neoliberalism: Exposing the Spirit of Our Age, 98–99