But while we thus find in the Son of God and in His atoning work the
foundation of the faith of our Church, many obstacles had been placed in
the way of securing this redemption. Legalistic conditions made it
impossible for the sinner to know that his sins had been taken away. It
was here that the Lutheran Reformation pointed the way to a return to
the simplicity of the Gospel by its Scriptural definition of
justification. _Sola fide_, by faith alone, was the keynote of the
Reformation. Be sure that you bring back _sola_ was Luther's admonition
to his friends, who went to Augsburg while he himself remained at
Coburg.

Thus justification by faith became the material principle of
Protestantism and a second foundation stone of Lutheranism. It is true
that Calvin and the Reformed churches also accepted this principle, but
they did not begin with it. Their system was based on the idea of the
absoluteness of God. The Lutheran system emphasizes the love of God to
all men; the Reformed system emphasizes predestination; which, by
selecting some, excludes the others. As the theologians describe it,
Lutheranism is Christocentric, Reform is theocentric.*
*Calvin, like Luther, read theology through Augustine and without
his ecclesiology, but from an altogether opposite point of view. Luther
started with the anthropology and advanced from below upwards; Calvin
started with the theology and moved from above downwards. Hence his
determinative idea was not justification by faith, but God and His
sovereignty, or the sole and all-efficiency of His gracious will.-Ibid.,
page 162.

A third principle relates to the means of grace. Here we have less
difficulty in discerning the line of cleavage which separates us from
Rome on the one hand and from the rest of Protestantism on the other