"What is Christianity? Not metaphysics, not mysticism, not a compilation of guesses at truth. It is the history of the seed of the woman—that seed the Word made flesh—the Word made flesh, the revelation of the invisible Jehovah, the representative of the eternal God, the medium of communication between the Creator and the creature, between earth and heaven.
And of this Christianity, what is the essential characteristic, indispensable feature from first to last? Is it incarnation or blood-shedding? Is it the cradle or the cross? Is it the scene at Bethlehem or at Golgotha? Assuredly the latter! "Eli, Eli, lama sabachthani," is no mere outcry of suffering nature, the cross is no mere scene of human martyrdom, and the great sepulchre is no mere Hebrew tomb. It is only through blood-shedding that conscience is purged; it is only at the cross that the sinner can meet with God; it is the cross that knits heaven and earth together; it is the cross that bears up the collapsing universe; it is the pierced hand that holds the golden sceptre; it is at Calvary that we find the open gate of Paradise regained, and the gospel is good news to the sinner, of liberty to enter in.
Let men, with the newly sharpened axes of rationalism, do their utmost to hew down that cross, it will stand in spite of them. Let them apply their ecclesiastical paint-brush, and daub it all over with the most approved of mediaeval pigments to cover its nakedness, its glory will shine through all. Let them scoff at the legal transference of the sinner's guilt to a divine substitute, and of that Surety's righteousness to the sinner, as a Lutherean delusion, or a Puritan fiction, that mutual transference, that wondrous exchange, will be found to be wrapped up with Christianity itself. Let those who, like Cain of old, shrink from the touch of sacrificial blood, and mock the "religion of the shambles," purge their consciences with the idea of God's universal Fatherhood, and try to wash their robes and make them with in something else than the blood of the Lamb; to us, as the saints of other days, there is but one purging of the conscience, one reconciliation, one healing of our wounds, the death of Him on whom the chastisement of our peace was laid, and one everlasting song, "unto him that loved us, and washed us from our sins in his own blood." —Horatius Bonar (1808-1889)
Excerpt is taken from Christ Is All: The Piety of Horatius Bonar (Haykin & Brooker, Reformation Heritage Books, Grand Rapids, Michigan 2007) Chapter 13 titled The shd blood of Christ: The foundation of Christianity