When did Prince start speaking in aphorisms?

The NYT quotes Prince:

"I always knew I had a relationship with God. But I wasn't sure God had a relationship with me."

This is in the format of any number of old quotes:

[Asked: do you believe in God?] The question is: Does God believe in me?

And:

[When asked if you've made your peace with God.] I did not know that we had ever quarreled.

The first quote appears in the movie (and the book?) "Lolita." The second was supposedly said by Henry David Thoreau (who also said "One world at a time" when asked if he'd thought about the afterlife).

Aphorisms rule. Here's a nice and incredibly cheap book of aphorisms I like. An ideal book in which to scribble marginalia.