I hear this now and again from religious people, especially Christians. It was going around on Twitter today. Apparently a few people found it pretty profound. It's superficial and designed to sound clever, esoterical and wise. It's also, indirectly an argument from authority. God exists and that's that. Of course it's has no logic and is pure nonsense. It might better be inverted to say Atheists wouldn't need to exist if there was a God.
I sometimes wonder if there's any point responding to such verbal emptiness.