"When it is a matter of bearing testimony, there can be only one theme and center of what I say. And that is the indication of the name of Jesus Christ as the essence and existence of the loving kindness in which God has taken to Himself sinful man, in order that he should not be lost but saved by Him. This name, and in the strict sense only this name, the name of the Helper, is what we know about help in need, and therefore can and must speak. This name is the word which we do not grudge our neighbor, but with which we have to greet him as a future brother. Where there is genuine love for the neighbor this name cannot and must not be withheld.
"The only word which is praise of God and a witness to the neighbor is a word which is praise of Jesus Christ and witness about Him. Every word which is that is true praise of God and a true witness to the neighbor. Such a declaration of the name of Jesus Christ will be a full recognition of what Jesus Christ is and of what has been done by Him. It will be a critical word, unsettling, pointing away, excluding the claims of all other names in which we might seek refuge. It will always be a word of thankful adoration before the majesty of free grace revealed in this name. But necessarily it will also be a word of confession, i.e., a word in which our recognition of this name as the name of the Lord is irrevocably revealed. But it will depend upon and maintain that assertion of the name which the name has created for itself among men.
"That means that it will be a churchly word, i.e., a word proceeding from the Church and calling to the Church. And its churchly character will consist concretely in the fact that it is basically an expository word, the explaining and applying of Holy Scripture as the primal witness to Jesus Christ which underlies and sustains all the rest. It is when I speak a word like this to my neighbor that I fulfill my responsibility to him. I tell him what I know of the other side of my and, as I hope, his need.
"This other side of the need, if indeed there is this other side, i.e., if God is manifest to man, is simply Jesus Christ. That God should be manifest to the neighbor in his need, that his need should have this other side, is something which I cannot control or foresee. But God can make use of my service to make it true. I have to show myself prepared and ready for this service by not refusing to the neighbor my word of witness. I refuse it if I am silent or if I speak of things which are irrelevant. In the latter case my words are just words: I do not love my neighbor in deed and in truth. If my witness is a witness to the name of Jesus Christ, it is not just a word, but as a word it is the most concrete act, in the strictly literal sense it is the 'expression' of praise of God and love to the neighbor.
"That it is not in my power to give this work the efficacy by which it is to the neighbor the fulfillment of revelation, the imparting of the Word and Spirit of God, by which therefore his need takes on that other side -- this limitation belongs to its very nature as witness. We cannot try to transcend the limitation without destroying its nature as witness. We have to respect the limitation, especially if we do not want to cease loving our neighbor. But within this limitation there can be no doubt that we not only say the right thing but in doing so do the right thing to our neighbor when, because we are really concerned about him, we speak to him freely about the name of Jesus Christ."
--Karl Barth, Church Dogmatics I/2, 443-44 (originally a single paragraph)