My following speculation is not what anyone will read in books or as Christian denomination dogma. My conjecture is that why Jesus had Paul aka Pharisee, awarded Roman citizen Saul and then Luke become involved is that the original expectation between God and his race of Angels (possible UIEs) was that Jesus's mission would NOT succeed due to the intractable dark nature of many ruling humans. So that God and his angels would need to take over control of the Earth from we disgusting, immoral, warlike, Earth monkeys. Something they probably greatly wanted to avoid in their precious galactic zoo but were frustrated over repeated failures over a millennium plus from Moses's days in trying to change sinful human behaviors. Thus Jesus may have been God's last final attempt to help we humans.
Instead, the followers of Jesus after the Resurrection, were quite successful at establishing a nascent Jerusalem based church, so changed from short term plans of End of Times, to a long term strategy. They were successful mainly because hundreds of followers really did see like a seeming true miracle from God, a resurrected Jesus in the flesh that no amount of threatened punishment even death by torture, could deter, if they also believed their own eternal life followed. The fact that so many believed they saw Jesus meant authorities could not simply deny whatever as the imagination of a few Zealots with agendas. If the Resurrection had just been an elaborate phony plan with Jesus actually suffering a horrible tortured death, his many followers would never had sacrificed their precious lives so. To have a long term chance of a Christian church succeeding required documenting in written form Jesus's mission period and Resurrection. Something simple oral tradition was weak at. However the 12 Apostles were not Greek language educated because they had not been selected to create a long lasting Christian church if the end was coming soon, so could not effectively record those times.
Thus Jesus, God, and his race of Angels went to wing it Plan B. Selecting the Jewish, prime Jesus persecutor Saul, was a incredibly wise plan, to spread the word around the Mediterranean beyond Israel and that did greatly succeed. Saul himself saw and that was so convincing that he as Saint Paul flipped his passionate thinking 180 degrees, then endured through hardships and pain through the rest of his life. The 3 synoptic gospels were gradually formed from fresh oral traditions of Jerusalem followers. If what someone wrote was incorrect, there were hundreds of believers that were still alive that could have refuted whatever. By time of the AD70 Roman army destruction of Jerusalem and temple, the 3 gospels may have been considered too weak in the most important message. So the Holy Spirit once again came down and inspired John to write his amazing gospel that better focused on eternal life as the gift believers followers would receive. Luke's ACTS document was also very important as it ties much together beyond the gospels.
And as I have written elsewhere, eternal life may be physically possible, not just some magic like miracle, once one understands that all Earth intelligent animal life is at its essence, complex oscillating electromagnetic fields nature termed brainwaves, and as such might arguable be transferred by some ultimate ancient entities into non-organic impedance matching containers, thus essentially immortal if not physically destroyed.