And the decree of Esther confirmed these matters of Purim; and it was written in the book.

And all things which are contained in the history of this book, which is called Esther.

And a saying of Esther hath established these matters of Purim, and it is written in the Book.

The order given by Esther gave the force of law to the rules about the Purim; and it was recorded in the book.

As "the book" elsewhere in Esther always means a particular book - "the book of the chronicles of the kings of Media and Persia" - Esther 2:23; Esther 6:1; Esther 10:2 it seems best to give it the same sense here.

The decree of Esther confirmed these matters - It was received by the Jews universally with all respect, and they bound themselves to abide by it.
The Vulgate gives a strange turn to this verse: Et omnia quae libri hujus, qui vocatur Esther, historia continentur; "And all things which are contained in the history of this book, which is called Esther."
The Targum says, And by the word of Esther all these things relative to Purim were confirmed; and the roll was transcribed in this book. The Syriac is the same as the Hebrew, and the Septuagint in this place not very different.

And the decree of Esther confirmed these matters of Purim,.... As a festival to be observed by the Jews in future generations:
and it was written in the book; either in this book of Esther; or in the public acts and chronicles of the kings of Persia; or in a book by itself, now lost, as Aben Ezra thinks, as many others are we read of in Scripture, as the books of the chronicles of the kings of Israel and Judah, &c.

Either - Who had received authority from the king. The book - In the records which the Jews kept of their most memorable passages.