Wherefore they called these days Purim after the name of Pur. They took the Persian word, that is, and gave it a Hebrew plural, either because the Persian method of casting involved the use of several lots, or because Haman cast "Pur" several times (Esther 3:7).
For all the words of this letter. i.e. "on account of what was said in Mordecai's letter to them" (Esther 9:20). And of that which they had seen, etc. "And on account of what they had themselves seen anti suffered."