Immanuel Kant claims that a good will is the only thing that can be considered "good without limitation." What does he mean by this?

Kant, the German Philosopher from the 18th century,
believed that good did not so much arise out of our experiences, or from agents acting
outside the physical self, but that humans through reason had developed morals - a sense
of right and wrong - and that a "good will" was intrinsic.  That is to say, humans had a
good will, or acted from that good will, because they believed in the moral goodness of
an act without any outside motivation to do so.  To put it another way, Kant was saying
that true goodness comes from the heart, not because of some reward or fear, so that
goodness of the human heart is unlimited because its source is within us.  It's a very
interesting and hopeful idea.