Now his parents went to Jerusalem [every year] at the feast of the passover.
And when he was [twelve years old,] they [went up] to Jerusalem after the custom of the feast.
And when they had fulfilled the days, as they returned, the child Jesus [tarried behind] in Jerusalem; and Joseph and his mother knew not of it.
But they, supposing him to have been in the company, went a day’s journey; and they sought him among their kinsfolk and acquaintance.
And when they found him not, they...
Luke 2:41–52