It seemed good to me also, having had perfect understanding of all things from the very first, to write unto thee in order, most excellent Theophilus (Luke 1:3).
God used Luke to chronicle the life of the early church in the acts of the apostles (Acts 1:1). He was with Paul at the close of Pauls ministry; only Luke is with me (II Timothy 4:11). All Scripture is given by inspiration of God, not just thoughts but the very words of the original autographs penned by the New Testament writers. Why then would Luke claim perfect understanding? To shed light on his claim, one must look at the adverb perfect.
This particular Greek adverb is also translated in Matthews Gospel as diligently. King Herod was perturbed by the birth of a rival king whose arrival on earth brought wise men bearing gifts. It was imperative that he locate the usurper. So he examined the wise men. The phrase used for this session is diligently inquired (Matthew 2:7,8,16) with diligently being the same adverb as Lukes perfect. Herod was so sure his diligent inquiry had netted the truth, he used it as the basis to slaughter the babies in Bethlehem. Luke was not a more truthful writer than the other New Testament writers. What one could say is that Luke gave attention to details.
Luke is the exact writer who through the inspiration of the Holy Spirit (10:33) recorded the Lords teaching about the Good Samaritan, the prodigal son (15:11), the rich man and Lazarus (16:19), and many others found only in Luke. Luke is the one who recorded Jesus Christs words to the dying thief, Today shalt thou be with me in paradise (23:43).
It is no wonder that Paul enjoyed Lukes company at the last, and it is no wonder that Luke could tell Theophilus (and us as we read Lukes work) that he was writing it all down in detail so that we all mightest know the certainty of those things wherein we have been instructed (Luke 1:4). CJH