Full Idea
Kant's first formulation of the categorical imperative is supposed to capture the widespread intuition that one ought not to make an exception of oneself.
Gist of Idea
The intuition behind the categorical imperative is that one ought not to make an exception of oneself
Source
report of Immanuel Kant (Groundwork of the Metaphysic of Morals [1785]) by James Gordon Finlayson - Habermas Ch.6:83
Book Reference
Finlayson,James G.: 'Habermas' [OUP 2005], p.83
A Reaction
Interesting. I always take the plain English version to be 'what if everybody did that?' Suppose I were to forgive everyone, except myself?