Matthew Poole and continuators on Luke 2:46

46 And it came to pass, that after three days, they found him in the temple, sitting in the midst of the Doctors, both hearing them, and asking them questions.

After three Days possibly here is to be understood from the time they first went from Ierusalem, one Day they went forward in their Journey, a second Day they were coming back, the third Day they found him, for it cannot be thought they should be in Ierusalem three days before they found him, considering that they found him in the Temple, which it is likely was the first place they sought for him in. It should seem that the Doctors of the Law gave a general liberty to any, to propound any Questions to them about the Law of God, to which they gave Answers. But it is very probable, that something more then ordinary appeared in him, that they admitted him to Sit amongst them, for tho themselves sate on Benches, yet their Auditors usually sate at their Feet, hence we read of Paul's being brought up at the feet of Gamaliel.