The self-forgetfulness of love

In Dietrich Bonhoeffer's study of the Sermon on the Mount, he discusses the extraordinary quality of the Christian disciple's life and the seeming contradiction that the disciples are to be the light of the world but at the same time should not make their Christian life visible. How do these two ideas go together? In explaining this, Bonhoeffer says something profound about the character of love itself.

Dietrich Bonhoeffer and confirmands, 1932

"From whom are we to hide the visibility of our discipleship? Certainly not from other men, for we are told to let them see our light. No. We are to hide it from ourselves. Our task is simply to keep on following, looking only to our Leader who goes on before, taking no notice of ourselves or of what we are doing. We must be unaware of our own righteousness, and see it only in so far as we look unto Jesus; then it will seem not extraordinary, but quite ordinary and natural. ...
     [Discipleship] means an exclusive adherence to him, and that implies first that the disciple looks only to his Lord and follows him. If he looked only at the extraordinary quality of the Christian life, he would no longer be following Christ. For the disciple this extraordinary quality consists solely in the will of the Lord, and when he seeks to do that will he knows that there is no other alternative, and that what he does is the only natural thing to do....
     The genuine work of love is always a hidden work. Take heed therefore that you know it not, for only so is it the goodness of God. If we want to know our own goodness or love, it has already ceased to be love. We must be unaware even of our love for our enemies. After all, when we love them they are no longer our enemies. This voluntary blindness in the Christian (which is really sight illuminated by Christ) is his certainty, and that fact that his life is hidden from his sight is the ground of his assurance...
    Genuine love is always self-forgetful in the true sense of the word. But if we are to have it, our old man must die with all his virtues and qualities, and this can only be done where the disciple forgets self and clings solely to Christ. When Jesus said: "Let not thy left hand know what thy right hand doeth," he was sounding the death-knell of the old man. Once again, who can live a life which combines [Matthew] chapters 5 and 6? Only those who have died after the old man through Christ and are given a new life by following him and having fellowship with him. Love, in the sense of spontaneous, unreflective action, spells the death of the old man. For man recovers his true nature in the righteousness of Christ and in his fellow-man."

Dietrich Bonhoeffer, The Cost of Discipleship 

(trans. R. H. Fuller. New York: Macmillan, 1963 [German: 1937]), 176-179.