Learn to eat of the tree of Knowledge, and of the tree of Life enjoy the fruit.
Gurnemanz is still not absolutely certain that Parsifal is pure and a fool, as he makes the decision to lead Parsifal to the castle of the Graal, for Gurnemanz sang after they both had walked a while: Now pay attention, and let me see, if you are a fool and if you are pure…! — The test, if he is a pure fool, shall come to Parsifal first in the Temple of the Graal! This point cannot be worked out further here.
Parsifal does not ask in the first act: What is the Graal, Parsifal asks, Who is the Graal?