John Gill Commentary Luke 2:47

"and all that heard him were amazed at his understanding and his answers." — Luke 2:47 (ASV)

And all that heard him were astonished
All in the sanhedrim, both the doctors, and their disciples, were amazed,

at his understanding ;
in the knowledge of the law, and of the Scriptures:

and his answers ;
which he returned to the questions the doctor's put to him, which were made with so much wisdom and judgment, that it was surprising in one of his years.