When Mary and Joseph find Jesus in the temple, he asks why they were looking for him. He says they should have known he must be in his Father’s house (or about his Father’s affairs). Luke presents this as Jesus’ own explanation of why he remained in the temple (Luke 2:48–49).
Luke narrates a family trip to Jerusalem for Passover when Jesus is twelve. On the return journey, his parents assume he is traveling with others, but he remains in the city. After a searching return, they find him in the temple engaging teachers with listening and questions, impressing those present. This scene comes at the end of Luke’s infancy and childhood material, following birth, early worship scenes, and earlier remarks about Jesus’ growth.
Luke presents Jesus as fully embedded in Jewish life: his family makes regular Passover pilgrimages to Jerusalem. The story assumes ordinary travel realities (large groups, children moving among relatives) and ordinary parental fear when a child is missing. The text also places Jesus, at age twelve, in the temple as an unusually perceptive participant.
A common mistake is to turn the wording into a slogan. The better reading keeps the phrase tied to the passage, the speaker, and the problem the book is addressing.
Start with Luke 2:48-49, then read the surrounding section so the answer stays connected to the passage's flow.
48When they saw him, they were astonished, and his mother said to him, "Son, why have you treated us this way? Behold, your father and I were anxiously looking for you."
49He said to them, "Why were you looking for me? Didn`t you know that I must be in my Father`s house?"