Full Idea
If there is no original being different from the world, if the world is without a beginning and without an author, if our will is not free and our soul is of the same corruptibility as matter, then moral ideas and principles lose all validity.
Gist of Idea
Without God, creation and free will, morality would be empty
Source
Immanuel Kant (Critique of Pure Reason [1781], B496/A468)
Book Reference
Kant,Immanuel: 'Critique of Pure Reason', ed/tr. Guyer,P /Wood,A W [CUO 1998], p.499
A Reaction
Atheism or determinism might lead to the collapse of your morality, if you had an amazingly inflated idea of the cosmic importance of human beings behaving well. My view is that morality just concerns important decisions made by healthy persons.