On the second day, Mary and Joseph returned to Jerusalem, which evidently took the whole day. Then on the third day they began searching for Jesus and found Him in the temple sitting among the rabbis listening to their teaching and asking them questions. Luke"s reference to His being in their "midst" suggests Jesus" centrality in this august group, though He was then a learner and not a teacher (cf. Psalm 119:99-100). [source][source][source]
"Already early in life Jesus values the pursuit of comprehending God, as he increases "in wisdom and stature" ( Luke 2:52). His approach to knowing God and seeking understanding pictures how we should pursue the same, even at a young age." [1][source]
Jesus" understanding and His answers amazed (Gr. existanto) them all (cf. Luke 4:32; Luke 9:43). One suspects that some of these rabbis remembered this incident when Jesus later became a popular teacher Himself. Obviously Jesus already had unusual wisdom and insight into the Scriptures, which were the center of these discussions. [2][source]