Luke 1:1–4 - "Inasmuch as many have undertaken to compile a narrative of the things that have been accomplished among us, just as those who from the beginning were eyewitnesses and ministers of the word have delivered them to us, it seemed good to me also, having followed all things closely for some time past, to write an orderly account for you, most excellent Theophilus, that you may have certainty concerning the things you have been taught."
With this introduction, we are made aware of the very purpose and background of Luke's writing. By the time that Luke wrote this letter and the book of Acts, many others had already written down the stories and sayings of Jesus. Much information in the first century was passed on by oral repetition. This is a lost form of communication in our day and time. They didn't just 'tell' a story, they would tell it and retell it. The next 'storyteller' would have heard it so many times that when he began this important function it had been committed to memory. It also was tested and verified by those who had also heard the story. Now, they also had written accounts that could be checked and studied. The result is that the story is correct.
The original 'storytellers' were eye-witnesses of the very events discussed. They lived with Jesus, talked with Jesus, and thus could speak with authority on what had happened. Luke examined and 'followed closely' all things. Having been a partner with both Paul and Peter, he was in a position to discern any differences and discrepancies. The nature of such 'following closely' can be seen in his precise mentioning of people, places, directions, terminology of people. While there are yet a couple of items that we moderns wrestle with on how such was understood by the original readers, the over-bearing reality is that Luke was a very precise student of his times.
Concerning the phrase 'write an orderly account', one writer commented:
According to the sense of the word orderly used in the original, an orderly account is one in which one says next what should be said next. It is an account which is not confused or haphazard. By no means is it true that the evangelist here promises to write a Gospel in which every event will be related in precisely chronological sequence.
By and large, the sequence of events as reported by Luke is chronological. On the other hand, with respect to individual details, this is by no means always the case. Study (a) Luke’s account of the three temptations (4:3–13), comparing it with that of Matthew (4:3–11); (b) the early place where Luke describes Jesus’ rejection at Nazareth (4:16–30), comparing it with the far later place in their respective Gospels where Matthew and Mark cover the same event (Matt. 13:54–58; Mark 6:1–6); (c) the problem posed by Luke 9:51; 13:22; 17:11 (three separate journeys to Jerusalem?); and (d) the question raised by Luke 22:19–23 (cf. John 13:30) as to whether Judas Iscariot partook of the Last Supper
This was so that the one who reads this can 'know assuredly' what was taught and believed by the first disciples of Jesus. Much change has taken place, many things have been denied, and many things have been added to the story by later peoples, but here we have the source to check and verify. We must take this seriously and always check our beliefs with the teachings of Jesus’ chosen apostles. God has revealed and preserved the good news concerning Jesus. Let us hold fast to His word.