Thanks for asking a question on thisisyourbible.com
Sanballat was an enemy of the Jews who lived during the time of the Jews' return from Babylonian exile. He tried to have the rebuilding of Jerusalem under Nehemiah stopped by sending false reports back to the Persian King, Artaxerxes Longimanus. When these efforts failed he tried to lure Nehemiah into a trap where he could be murdered. All of his efforts were unsuccessful. You may read of Sanballat in the book of Nehemiah chapters 2, 4, and 6.
I hope you have found this helpful.