How did Luke find out all the stuff that he recorded? Obviously he heard the teachings of Jesus, which were passed on by all the disciples and the later Christians, but how did he learn all this intimate stuff about Jesus' birth and early years?
We don't know for certain, but experts strongly suspect that he interviewed Mary. Today we hear something that sounds just like something your mother may have said to you "Your father and I have been frantic, searching for you everywhere."
Of course these days, children have much less chance to wander off by themselves and get lost. We are all far too aware of the dangers for that. Jesus would have enjoyed more freedom. On a rare trip to Jerusalem, he would have spent days with his extended family and friends, perhaps only seeing his parents in the evening when they broke their journey at some overnight resting place.
Galilean Jews made the long trip to Jerusalem only occasionally. At Passover certainly, once a year, but perhaps no more often than that. So Jesus would have regarded this as a holiday. So would the rest of his family. Their guard would be down, fun would be had, celebrations enjoyed. Perhaps this was Jesus' Bar Mitzvah year - even more special.
Whatever the reason, when they started for home, Jesus stayed behind in the Temple. It wasn't until the evening halt that Mary and Joseph missed him. After an anxious night they turned round and headed back to Jerusalem. Arriving late, they couldn't find him before having to spend another, even more anxious night without him. Every parent's nightmare.
I can remember one holiday on the beach, losing sight of my son. I found him after 5 minutes - hardly a disaster - but the memory stays with me. Imagine 48 hours having gone by, and still no sign of him.
Exhausted, desperate, sick with worry, Jesus' parents stumbled into the Temple. Had they finally decided to pray for help? Or maybe they hoped that someone there would have seen him, or be willing to put up a "Lost Boy" poster.
It took a while to find someone important. Apparently they were all in a meeting and not to be disturbed. Joseph would have waited, but Mary, driven by her mother's imperative, walked straight in.
And there he was.
He was the reason for the meeting. A great theology debate was in session, and a 12 year old boy was calling the shots. Mary scolded the boy, apologised to the elders, and hustled him out. And Jesus gave the original wide-eyed innocent stare: "But why did you need to search? Didn’t you know that I must be in my Father’s house?"