In The Alchemist, what was the point of the boy becoming the wind?

The final test that
Santiago undergoes in this story is to transform himself into the wind. This is something that
he is only able to do with the help of the desert, the sun and the wind, and this section of the
book charts the conversations that he has with each of these entities. This is a vital part of
the process of transformation that Santiago goes through as he purifies himself in order to
achieve his Personal Legend. Santiago has to learn to communicate with nature in the common
language of the world. This helps Santiago to realise what the alchemist repeatedly tells him,
that all of nature is part of the same essence, however small or big, and if he is able to
connect with a grain of sand he is connecting with God himself. Note how his transformation into
the wind is described:

The boy reached through to the Soul
of the World, and saw that it was a part of the Soul of God. And he saw that the Soul of God was
his own soul. And that he, a boy, could perform miracles.

This test of transforming himself into the wind is therefore so important because
Santiago needs to learn the pantheistic message that dominates this book, and how he is a part
of nature, a part of God, and therefore able to accomplish miracles. Santiago is only able to
achieve his Personal Legend through learning this vital lesson.