Jamieson, Fausset and Brown on Ezra 6:11-12

11-12. whosoever shall alter this word--The warning was specially directed against the turbulent and fanatical Samaritans. The extremely favorable purport of this edict was no doubt owing in some measure to the influence of Cyrus, of whom Darius entertained a high admiration, and whose two daughters he had married. But it proceeded still more from the deep impressions made even on the idolatrous people of that country and that age, as to the being and providence of the God of Israel.