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 seed, the matters of the fastings and their cry.

Esther 4:3

And in every province whithersoever 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, assemble all the Jews that are present in Shushan, and fast ye 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 to the king, which is not according to the law; and if I perish, I perish.

Jonah 3:2-9

Arise, go to Nineveh, that great city, and preach to it the preaching that I bid thee.

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 them, and upon their seed, and upon all such as joined themselves to them, so as it should not fail, that they would keep these two days according to their writing, and according to their appointed time every year;

The fastings

Esther 4:3
And in every province whithersoever 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 to Nineveh, that great city, and preach to it the preaching that I bid thee.