"Man, in his natural spirit of self-justifying legalism, has tried to get away from the cross of Christ and its perfection, or to erect another cross instead, or to setup a screen of ornaments between himself and it, or to alter its true meaning into something more congenial to his tastes, or to transfer the virtue of it to some act or performance or feeling of its own. Thus the simplicity of the cross is nullified, and its saving power is denied. For the cross saves completely, or not at all.
Our faith does not divide the work of salvation between itself and the cross. It is the acknowledgment that the cross alone saves, and that it saves alone. Faith adds nothing to the cross, nor to its healing virtue. It owns the fullness, and sufficiency, and suitableness of the work done there, and bids the toiling spirit cease from its labours and enter into rest.
Faith does not come to Calvary to do anything. It comes to see the glorious spectacle of all things done, and to accept this completion without a misgiving as to its efficacy. It listens to the “It is finished!” of the Sin-bearer, and says, “Amen.”
Horatius Bonar (1808-1889) Excerpt taken from "The Everlasting Righteousness" by Horatius Bonar first published 1874, Banner of Truth 1993