What did the man tell Santiago at the Pyramids after he beat him?

The quote goes like this,

In my dream," the thief says, "there was a sycamore growing out of the ruins of the sacristy, and I was told that, if I dug at the roots of the sycamore, I would find a hidden treasure. But I'm not so stupid as to cross an entire desert just because of a recurrent dream."