WHO said: "sinful macduff,/ they were all struck for thee naught that I am,/ not for their own demerits, but for mine,/ fell slaughter on their souls. heaven rest them now" and WHAT does it means?

Macduff says this about his family's slaughter by the murderers that Macbeth hires. He is speaking, in a way, to himself, noting that they were only killed because they were his family. They were not guilty in any way and did not deserve to be killed.