In thinking about such issues as evangelism, apologetics, missions, and Christianity's relationship to other religions, I ran across an older but excellent and informative article: I. Howard Marshall, "Dialogue with Non-Christians in the New Testament," Evangelical Review of Theology (16): 28-47. Unfortunately, this article does not appear to be online. Nevertheless, it is essential reading for all Christians interested in sharing the gospel with others. It begins where we all should start in working through these issues--God's Word. While I'd love to post the whole article (but am equally sure that I cannot!), below is the introduction to whet your appetite. Hopefully it will serve as a "hook," leading you to find a copy and read it in its entirety.
The place of dialogue with non-Christians in relation to the evangelistic task of the church has received renewed attention recently in the pages of the Evangelical Review of Theology. It is clear that some Christians regard dialogue as an important form of witness, and think that the church's evangelistic task should be carried on by means of dialogue as well as by proclamation.
We may roughly contrast the two possible approaches as follows. In proclamation the evangelist (X) has a message (G--the gospel) which he communicates to his hearer (Y) as something which is to be accepted or rejected; the evangelist himself has received this unchanging message, and he communicates it virtually without change. In dialogue, however, the message is not something which the evangelist already possesses in normative form. Rather he must enter into discussion with his hearer, both participants contributing to the dialogue and thus together reaching an understanding of the gospel.
A. PROCLAMATION
G ---> X ---> Y
B. DIALOGUE
X ---> G <--- Y
The question which is posed by juxtaposing these two types of approach is whether the Christian message is something 'given' to the evangelist which is passed on unchanged to the potential convert, or whether the truth of the gospel is something that emerges in the course of dialogue. Obviously the issues are not as sharp as this in practice. Any evangelist must shape his proclamation to the situation and character of the hearer; it is no use speaking in German to somebody who only understands Tamil, and illustrations and concepts must be chosen which will be intelligible to the hearer. Similarly, even in a situation of dialogue the evangelist will have some understanding of the gospel, even if his understanding of it may undergo radical alteration in the course of dialogue. Nevertheless, it is still necessary to ask whether the essential content of the gospel is something 'given' to the evangelist or can undergo radical alteration in a common search for truth along with a non-Christian.
It is surely essential that in discussing this matter we have a clear understanding of what is meant by 'dialogue' in the New testament and determine whether it was practised as a means of evangelism. We shall look first at the meaning of the Greek verbs which suggest the idea of dialogue, and this will involve us in a study of the church's evangelism as portrayed in Acts. From there we shall turn back to the synoptic gospels [Matthew, Mark, and Luke] to see whether the dialogue form can be found there, and then we shall move forward to see whether Paul's letters reflect the use of dialogue, and finally we shall consider the Gospel of John as a source for dialogue. The essay will close with some brief conclusions.