What echo of his former self is reflected in Macbeth's final speech?

Macbeth speaks his final speech when the joined forces of Malcolm and Macduff are coming to his castle to defeat him. In a brief moment, we can see an echo of Macbeth's former self when he hears the cry of a woman, and he thinks to himself that once upon a time he would be scared of such a cry and maybe stop fighting, but that time is long gone. He has committed so many atrocities that nothing can startle him now.