Drawing up an account

The Gospels have been attacked us un-credible biased witness. And while it is true that they are biased, every source of any event is biased, I think it is untrue that the Gospels are not a credible account of what happened, indeed they are written closer to the events than many other ancient literature that we take as truth was and hostile writers like Josephus often back up that what they were saying took place did take place.

But what do the Gospel's say about their own purpose, well let's look at Luke:
Many have undertaken to draw up an account of the things that have been fulfilled among us, 2 just as they were handed down to us by those who from the first were eyewitnesses and servants of the word. 3 With this in mind, since I myself have carefully investigated everything from the beginning, I too decided to write an orderly account for you, most excellent Theophilus, 4 so that you may know the certainty of the things you have been taught. (Luke 1:1-4 NIV)
There is no denying that Luke has a theological bent as early as the first verse. He talks about how these things have been "fulfilled among us", so it gives away what Luke already thinks. Although we also gather Luke's audience from this passage, Luke would seem to be writing to people who already know about Jesus, Luke isn't writing an evangelistic work necessarily but he is writing an account of what had happened.

We often refer to the Gospels as "Biographies of Jesus" and no where is that more true than in the Gospel of Luke, that is Luke's purpose in writing and he writes as a biographer looking for evidence, and making a measured account. If it is a biography of Jesus we want, then Luke is probably the best place to look.