Actually, the best way for the New Testament documents to be understood by, and useful to, citizens of the 21st Century is to recognize that these documents were not directed to us. Nor were any of these documents written to convince skeptics even in that day. They were all internal documents for a first-century Jewish sectarian movement that grew and ultimately came to be called Christianity. The documents were written for various specific purposes from and to participants in that movement who had already come to a conviction by word of mouth about Jesus of Nazareth being the Messiah of Israel. If it’s primary sources you want, recognize that’s exactly what you have. Even what Luke, who was himself not an eyewitness to Jesus, wrote was merely to give more precision to what participants in this movement had already been taught orally (see Luke 1:1-4).
(This first appeared as a comment on Matthew Paul Turner’s blog.)