Joseph and Mary left Jesus (Jesus never left them) and after recognizing it (that apart of them were missing) they turned back to find (in search of him) and they found him.
This is symbolic to us his lost sheep. When we stray away. Jesus doesn’t leave us we stray away from him. Here’s hope for those who stray away from him. If you search for him you will find him.
13 You will seek me and find me when you seek me with all your heart.