Esther 8:17
“And in every province, and in every city, whithersoever the king’s commandment and his decree came, the Jews had joy and gladness, a feast and a good day. And many of the people of the land became Jews; for the fear of the Jews fell upon them. ”
KJV
Read in Esther 8Meaning
The decree changes the Jews' public position throughout the empire. The final clause describes people aligning themselves with the Jews under the impact of this reversal; the verse itself does not explain the depth or motives of every such identification.