Esther 9:31

To confirm these days of Purim in their times appointed, according as Mordecai the Jew and Esther the queen had enjoined them, and as they had decreed for themselves and for their descendants, concerning the matters of the fastings and their lamentations.

Esther 4:3

And in every province, wherever the king's commandment and his decree came, there was great mourning among the Jews, and fasting, and weeping, and wailing; and many lay in sackcloth and ashes.

Esther 4:16

Go, gather together all the Jews that are present in Shushan, and fast for me, and neither eat nor drink three days, night or day: I also and my maidens will fast likewise; and so will I go in unto the king, which is not according to the law: and if I perish, I perish.

Jonah 3:2-9

Arise, go unto Nineveh, that great city, and preach unto it the preaching that I bid you.

Treasury of Scripture Knowledge

Summary

To confirm these days of Purim in their times appointed, according as Mordecai the Jew and Esther the queen had enjoined them, and as they had decreed for themselves and for their seed, the matters of the fastings and their cry.

And for their seed

The fastings

Bible References

And for their seed

Esther 9:27
The Jews ordained, and took upon themselves, and upon their descendants, and upon all such as joined themselves unto them, so that it should not fail, that they would keep these two days according to what was written, and according to their appointed time every year;

The fastings

Esther 4:3
And in every province, wherever the king's commandment and his decree came, there was great mourning among the Jews, and fasting, and weeping, and wailing; and many lay in sackcloth and ashes.
Jonah 3:2
Arise, go unto Nineveh, that great city, and preach unto it the preaching that I bid you.