The Tetrapolitan Confession was written mostly by Bucer and Capito. It is the oldest Reformed confession and served as the confessional statement for the four German Reformed cities of Strasburg, Constance, Memmingen, and Lindau.
This is what it has to say about justification by faith:
IV. On Justification by Faith
That our preachers attribute so much to faith is not at all their opinion, as if salvation and piety would stand in idle thoughts and in a faith which would be without love, which one calls an unformed faith, but this is held for the reason that we have to confess that nobody can become pious and saved unless he supremely love and most earnestly imitate God. For whom He did foreknow (writes St. Paul), He did also predestinate to be conformed to the image of His Son; and that, without doubt, as in the glory of the blessed life, so also, in the diligent exercise of innocent and very pious lives. For we are each made by Him, created unto good works, Ephesians 2:10. Now it is not possible, however, that somebody loves God above all things and earnestly imitates His goodness unless he knows Him and turns to Him for all good. For that reason, we could never in any other way become righteous and pious as well as saved, since our salvation is true piety, than that above all, we are endued by God with the gift of faith through which we accept the Gospel; and then, assured out of the same that God has accepted us as His children and wants eternally to prove His fatherly goodness, we cling completely to His will. Such faith, St. Augustine calls an evangelical faith which then is active through love. And it is through this faith that we are born anew and the image of God is brought forth again in us. Through this faith, we become good, we who are born evil and from youth have turned all our thoughts toward evil. Then, by this faith we become completely filled with God, the eternal and everywhere overflowing well of goodness, and thus we become of a divine kind, which means that we show ourselves soon to other people as gods, that is [as] true children of God, in that we through love further the benefit of everybody and don’t ever withhold any possible effort. For as John has written, whoever loves his brother, walks in the light and is born of God; [he is] completely given to the new and old commandment of mutual love. This love is, then, the fulfillment of the law as St. Paul says: The whole law was fulfilled in one word, namely this one; Love your neighbor as yourself, Galatians 5:14. For all that is given in God’s law is directed towards and requires that we are finally, completely reformed and renewed to the image of God, so that we are wholly good, willing, ready and also capable to advance the benefit of men. [The above] may not be attained in us through a shorter way than if we are decorated with all sorts of virtues and consequently are in accordance everywhere with the law. For how can somebody achieve and accomplish all to the betterment and building up of the community of God, and thus, according to the law which therefore is the special task of a Christian man (1 Corinthians 10:23), who does not think, speak and act all to the best, and thus possesses now the treasure of all virtues?
Pretty neat stuff.