1)
Who said this?
1.
Rashi: This is the text of the letter that the king sent to greet all nations.
2)
What do we learn from "Di Dayarin b'Chol Ar'a"?
1.
Malbim: He ruled over the entire land.
3)
What is "Yisgei"?
1.
Ibn Ezra: It should increase. This is like "Hen Kel Sagi."
