Luke 2:41-44

Now every year his parents went to Jerusalem for the festival of the Passover. And when he was twelve years old, they went up as usual for the festival. When the festival was ended and they started to return, the boy Jesus stayed behind in Jerusalem, but his parents did not know it. Assuming that he was in the group of travelers, they went a day's journey. Then they started to look for him among their relatives and friends.