Bṛhadāraṇyaka Upaniṣad ("Great Forest Teaching") 6.2.3

6.2.3

vettha yathemāḥ prajāḥprayatyo vipratipadyantā

The king said: 'Do you know how men, when they depart from here, separate from each other?' 'No,' he replied.
'Do you know how they come back to this world?' 'No,' he replied.
'Do you know how that world does never become full with the many who again and again depart thither?' 'No,' he replied.
'Do you know at the offering of which libation the waters become endowed with a human voice and rise and speak?' 'No,' he replied.
'Do you know the access to the path leading to the Devas and to the path leading to the Fathers, i.e. by what deeds men gain access to the path leading to the Devas or to that leading to the Fathers? For we have heard even the saying of a Rishi: "I heard of two paths for men, one leading to the Fathers, the other leading to the Devas. On those paths all that lives moves on, whatever there is between father (sky) and mother (earth)."'
Svetaketu said: 'I do not know even one of all these questions.'

Then the king invited him to stay and accept his hospitality. But the boy, not caring for hospitality, ran away, went back to his father, and said: 'Thus then you called me formerly well-instructed!' The father said: 'What then, you sage?' The son replied: 'That fellow of a Râganya asked me five questions, and I did not know one of them.'
'What were they?' said the father.
'These were they,' the son replied, mentioning the different heads.