Full Idea
That what happens necessarily, spontaneously and without any purpose, may henceforth appear to be done for some purpose, and strike man as rational and an ultimate commandment, the ethical teacher comes on stage, as teacher of the purpose of existence.
Gist of Idea
The ethical teacher exists to give purpose to what happens necessarily and without purpose
Source
Friedrich Nietzsche (The Gay (Joyful) Science [1882], §001)
Book Reference
Nietzsche,Friedrich: 'The Gay Science', ed/tr. Kaufmann,Walter [Vintage 1974], p.75
A Reaction
This doesn't look like much of a solution to the problem of nihilism, unless the teacher plants an idea in us which endures and grows. Nietzsche's 'eternal recurrence' was supposed to be just such an idea.