“and when they had fulfilled the days, as they were returning, the boy Jesus stayed behind in Jerusalem. Joseph and his mother didn’t know it,”
Luke 2:43 (WEB)
Context Reading
41His parents went every year to Jerusalem at the feast of the Passover. 42When he was twelve years old, they went up to Jerusalem according to the custom of the feast; 43and when they had fulfilled the days, as they were returning, the boy Jesus stayed behind in Jerusalem. Joseph and his mother didn’t know it, 44but supposing him to be in the company, they went a day’s journey; and they looked for him among their relatives and acquaintances. 45When they didn’t find him, they returned to Jerusalem, looking for him.