Why do you think the alchemist tells santiago the story about the man’s dream about the two sons (the poet and the soldier)?

Explanation:  One of the basic messages of this story told by the alchemist to Santiago is that if one wants to fulfill his dreams and live his personal legend, he often has to give up worldly wealth and glory, to go through certain sufferings and temptations, in order to come to fulfillment of your dreams. It is nothing more than a paraphrased statement of Christ himself from the Bible who said that man cannot have two masters, because where man's treasure is, there will be his heart, alluding to the kingdom of heaven. It is not by accident that in the alchemist's story one of the sons was the famous Roman centurion, who by his words and faith remained immortalized in the Bible.

Namely, that connection with the Bible is logical, because whoever strives for his treasure in heaven is the one who follows his dreams and wants to fulfill them. His master is in heaven as Christ said, or in the alchemist, his dreams. Thus, that emperor's son, a poet, eager for glory on earth, received it, he was well known and admired all over the empire. The other son, who humbly and faithfully served as a soldier, had so much natural faith in himself, that upon seeing Christ, he recognized that it was enough for Christ to say a single word, and the servant of the centurion would be healed. Even the centurion did not consider himself worthy of Christ to enter to his house, talks about his modesty. This proved to be eternal, that is, the aspirations of the centurions were not earthly glory, but treasure in heaven. That is why he remained recorded in the Bible, unlike his brother, whom no one knows today.  

This can be seen from the explanation given by the angel to the father of these two sons, since he died. After father's death, no one knew about the poet, and everyone admired the centurion and his faith. It also shocked the father who, after his death, allowed by the angel to see the mood and surroundings of his sons. The angel went on to explain that the poet, seeking the earth glory, received it. Also centurion, he got what he wanted, living modestly and following his dreams he received eternal glory. So it is with anyone who pursues his dreams, and so does Santiago, and that is why whenever he thought he had settled down and made enough money, he lost everything again and moved on to his dreams. Losing all of his earthly treasure, he went on to dream.

they encountered severe weather for which they were poorly prepared.