John Gill Commentary Luke 2:45

"and when they found him not, they returned to Jerusalem, seeking for him." — Luke 2:45 (ASV)

And when they found him not
In the company that came from Jerusalem with them, nor among any of their relations and friends, with whom they supposed he was:

they turned back again to Jerusalem ,
that is, the next morning, for it can hardly be thought they would set out that night, after they had travelled all day, without taking some repose:

seeking him ;
at Jerusalem, in the streets and broad places of it; a figure of the church and ordinances, where souls look for, and inquire after their beloved, when they have lost him, (Song of Solomon 3:1–3) .