Geshem was an Arabian leader who opposed Nehemiah. Under the Persian Empire he was appointed leader of a minor Arabian group of people near Judea, and it seems that he was determined to hold on to his power by making certain that no one else around him grew too strong.
But then came Nehemiah, a Jew who had served in the Persian royal court and who was now planning to rebuild the walls of Jerusalem, Judea’s capital city. What would this mean for Geshem and his small nation? Would Geshem’s power be overshadowed or even brought to an end by the Judeans? Something had to be done. So Geshem, together with leaders from other surrounding nations, began to ridicule Nehemiah and his plans, even accusing him of conspiring to rebel against the Persian Empire (Nehemiah 2).
But Nehemiah was not distracted from his goal, and the walls were soon completed. All that was left was to put the gates in place. Now what was Geshem going to do? So Geshem and the other leaders hatched a more sinister plot: lure Nehemiah to a place outside his jurisdiction and do him harm—perhaps even kill him! They sent him several messages inviting him to meet on the plain of Ono to the northwest of Judea, but Nehemiah wisely declined.
They accused him again of plotting to rebel against the Persians, but Nehemiah continued to trust in the Lord, and finally the project was completed (Nehemiah 6).
The Bible does not record anything further about Geshem, so we never learn whether his fears of losing his power were ever realized.
The Persian Empire continued to rule over Judea and northern Arabia for another hundred years. Their rule came to an end around 333 BC when Alexander the Great swiftly took over the Persian Empire in about twelve years.