what he did

According to Christian belief, Jesus is our Saviour, not by virtue of what he said, not even by virtue of what he was, but by what he did. He is our Saviour, not because he inspired us to live the same kind of life that he lived, but because he took upon himself the dreadful guilt of our sins and bore it instead of us on the cross. Such is the Christian conception of the Cross of Christ. It is ridiculed as being a "subtle theory of the atonement." In reality, it is the plain teaching of the word of God; we know absolutely nothing about an atonement that is not a vicarious atonement, for that is the only atonement of which the New Testament speaks. And this Bible doctrine is not intricate or subtle.

On the contrary, though it involves mysteries, it is itself so simple that a child can understand it. "We deserved eternal death, but the Lord Jesus, because he loved us, died instead of us on the cross"--surely there is nothing very intricate about that. It is not the Bible doctrine of the atonement which is difficult to understand--what are really incomprehensible are the elaborate modern efforts to get rid of the Bible doctrine in the interests of human pride.

Modern liberal preachers do indeed sometimes speak of the "atonement." But they speak of it just as seldom as they possibly can, and one can see plainly that their hearts are elsewhere than at the foot of the Cross. Indeed, at this point, as at many others, one has the feeling that traditional language is being strained to become the expression of totally alien ideas.

J. Gresham Machen, Christianity & Liberalism, p. 118-9