It has been a real joy to read through again (but this time in greater depth) Aurelio Garcia's "The Theology of History and Apologetic Historiography in Heinrich Bullinger: Truth in History." Having met him at a recent conference in Zurich adds to the joy of rereading through this seminal work.
I was struck by footnote 40 on pages 50,51.
"There is yet another crucial point lacking in Wayne Baker's discussion of the covenant. any notion that the human partner in the covenant stands on an equal footing to give a quid pro quo obedience to God in exchange for salvation, misses this cardinal point. God's offering of the covenant is already a might act of grace, for he has the right as creator to demand all obedience, yet he condescends to pact with us, accepting our obedience - which is Christ's obedience in us, through the Holy Spirit - in exchange for his love for us. We do not stand in equal footing with God; rather God adapts himself to us in the form of covenant, graciously making up for our creatureliness and our sinfulness. We could even describe this adaptation as as sort of make-belief by God, except, and this is the beauty of it all, that the ultimate accommodation of God to us is his incarnation in Jesus Christ. And again we are back to Christ as the testament. Remember too that Christ is both in a sense the divine and the human partner. Thus Bullinger's constant stress on the two natures of the Lord. Therefore once more the equivalency between testament and covenant shows up. Christ is God's promise to us, he is the fulfillment of that promise. Christ is also God offering the covenant, he is too humanity fulfilling the covenant."