It isn't difficult to see just how Luke had modelled and shaped the material he gains from his sources...

• He revises them in distinctive ways. He's much more likely to alter the beginning and the end of a pericope rather than the stuff in the middle. This suggests that he's concerned to draw out the meaning of the story or saying more fully and clearly than the source he is using - but not to alter its details. He doesn't feel free to `improve on' stories to make them more dramatic or spectacular.

• He often telescopes stories. Rather than adding on new features, wonders and marvels to stories he copies from Mark, he often summarizes them. This again is an indication that we're dealing with a serious historian, interested in the meaning of events, rather than an uncritical manufacturer of bigger and better fairy tales.

• He doesn't often intertwine his sources. His strategy seems to be to arrange his material in blocks, taking chunks from his different sources in turn. Howard Marshall says: `Here his practice stands in contrast with that of Matthew who groups material from different sources thematically. This consideration suggests that Luke was anxious to pass on the contents of his sources basically unchanged rather than to attempt an altogether new picture on the basis of a fresh combination of them.'

• He follows the same general outline of Jesus' story which he finds in Mark. But he's not really interested in the micro-chronology of when exactly things happened in detail; rather he presents a general picture of the kinds of things Jesus was apt to say and do, without being too bothered about what happened exactly when. He puts together incidents which comment on one another, even if they didn't strictly happen one after another. He is interested in macro-chronology, however - in other words, the major historical events which have a bearing on his story. For instance, he's the only Gospel writer who attempt to set Jesus within the context of his own day, the historical events unfolding at his birth, the political situation of occupied Palestine.

• He sometimes fine-tunes his sources to make them just a little more accurate. Herod is vaguely called a `king' in Mark; Luke makes him a `tetrarch' (which he was). The seed falling on the rock (Luke 8:6) had no `moisture' rather than `no root'.

• There are some small details which have been altered for a wider audience - for example, descriptions of Palestinian scenery which wouldn't have been understood by Greeks or other foreigners, where Luke has substituted a more recognizable word for the local word. And sometimes `the language and thought are more Hellenistic than Palestinian' (Marshall). But it isn't right to claim - as some critics do - that the original Gospel has been altered into a Greek form to make it acceptable to a new audience. There are little changes. in the interests of increased understanding, but not a radical rewriting of the Christian message by a Syrian-Greek spin-doctor!

• Although he alters his sources (such as Mark) in order to improve the Greek, he does this much less often when it comes to the sayings of Jesus. (`In the narrative material... we encounter the Lucan linguistic peculiarities four times as often as in the Jesus-sayings' - W G Kummel, Introduction to the New Testament.) He is obviously concerned to reproduce the things Jesus said with as little alteration as possible.