זוהר שמות — דף קסג ע”ב

What benefit does this accuser gain when the wicked obey him? Even though he has no real benefit of his own, he fulfills his Master command. When the wicked obey him, he grows stronger in his power, just as the Angel of Death gains strength when he leads men astray and kills them. Just as the side of life is strengthened when people walk the righteous path, so this accuser strengthens when the wicked submit to him and he rules over them. Happy are those who merit to overcome and subdue him, thereby earning the World to Come.