Kevin Vanhoozer has recently written, “Justification by faith alone in Christ alone”, is the instrument by which our relation to God changes from that of a guilty party before a judge, to that of a child before his/her loving Father.” (Wrighting the Wrongs of the Reformation: The State of the Union with Christ in St. Paul and Protestant Soteriology” in Jesus, Paul and the People of God: A Theological Dialogue with N.T. Wright. Edited by Richard Hayes and Nicholas Perrin (IVP, 2010)).
Vanhoozer is picking up on the crucial turn in Calvin’s exposition of redemption in book III of the Institutes. The judicial relation between sinful creature and Creator undergoes this massive shift and changes to a familial relation between a parent and their adopted child. In theological language the shift takes place as justification gives way to union. The forensic relationship of judge and accused is transformed by the verdict announced by God because of Christ. The (rightly) accused sinners are not only declared innocent and members in good standing before the divine covenant, but also in this very same act, they are declared to be children of their heavenly father.
As Vanhoozer says, “Might it be that the law court in which the justifying verdict is read out is also an adoption court, such that in declaring men and women his children God assigns them all the rights appertaining thereunto, including the incalculable privilege of calling God “Father” and the concomitant eschatological privilege of having the Spirit of the Father’s Son dwell in our hearts.” Yea and Amen!!