They’re studying covenant theology at Mars Hill. (HT: Austin Britton)

For those just getting started in covenant theology I recommend:

“A Brief History of Covenant Theology.”

God of Promise: Introducing Covenant Theology. It is biblical, accessible, clear, and the state of the art.

For more advanced reading, one of the classic texts is Herman Witsius,Economy of the Covenants.

For more on the history of covenant theology see R. Scott Clark, Caspar Olevian and the Substance of the Covenant: The Double Benefit of Christ.

There are more resources here and here.