John Gill Commentary Esther 9:30

"And he sent letters unto all the Jews, to the hundred twenty and seven provinces of the kingdom of Ahasuerus, [with] words of peace and truth," — Esther 9:30 (ASV)

And he sent letters unto all the Jews
That is, Mordecai did, signed in the queen's name, and his own:

to the hundred twenty and seven provinces of the kingdom of Ahasuerus ;
among which was Judea, that was become a province, first of the Chaldean, now of the Persian empire, see (Ezra 5:8) to whom also these letters were sent, directing and ordering the Jews there to observe these days, who were also concerned in the deliverance wrought:

with words of peace and truth
exhorting them to live in peace with one another, and their neighbours, and to constancy in the true religion; or wishing them all peace and prosperity in the most loving and sincere manner.