"The whole Passover ritual could be summarized in a single commandment:
'You shall tell your son.'
This is why at the beginning of the Haggadah the child asks four questions:
'Why is this night different from all other nights?
Why do we only eat matzah?' and so forth.
According to the law, if there is no child present, or if an adult celebrates Passover alone, he must ask the questions, even though he is supposed to 'know' the answers.
It is customary in certain communities for adults to ask the questions, because on Passover, we should, in a sense, become children.
This is also why in the Bible, Passover is called the 'spring holiday.'
On Passover, nature as a whole begins to blossom and man's renewal coincides with that of nature.
The Sages have pointed to the parallel between the word nitsan, 'bud,' and Nisan, the month in which Passover takes place.
It is a true renaissance.
We become children once again, and all we can do is ask questions."
From The Seven Lights by Rabbi Adin Steinsaltz