Albert Barnes on Luke 2:49

How is it, &c. Why have ye sought me with so much anxiety? Mary should have known that the Son of God was safe; that his heavenly Father would take care of him, and that he could do nothing amiss.

Wist ye not. Know ye not. You had reason to know. You knew my design in coming into the world, and that design was superior to the duty of obeying earthly parents, and they should be willing always to give me up to the proper business for which I live.

My Father's business. Some think that this should be translated "in my Father's house" -- that is, in the temple. Jesus reminded them here that he came down from heaven; that he had a higher Father than an earthly parent; and that, even in early life, it was proper that he should be engaged in the work for which he came. He did not enter, indeed, upon his public work for eighteen years after this; yet still the work of God was his work, and always, even in childhood, it was proper for him to be engaged in the great business for which he came down from heaven.

(z) Jn 5:17, 9:4