I’ve written a few slightly different versions of this (had-to-be-this-way) convoluted declaration. This specific one is from 2014:
I teach, which is simply to say that I "tell"—not that I cannot keep a secret; and yet there is a secret that I cannot keep . . . or tell; mostly, I tell, as often and in as many ways as I am given the occasion, that there is a secret that I cannot by any means keep or tell.