Who was Mordecai?

Mordecai was a Godly man who lived in Persia (now Iran).  Mordecai adopted his orphaned cousin (Esther 2:7) Hadassah (Esther) and raised her as if she were his own daughter.  Esther received guidance from Mordecai throughout her life.    

Mordecai "sat in the king's gate" (Esther 2:21). While in office, Mordecai learned of a plot by eunuchs to put the king to death and was rewarded for his devotion. Haman, who also served on the king's court, holding the highest position, demanded that others bow before him. Mordecai refused stating Jewish Law (Exodus 20:5). This created such hatred towards Mordecai and the Jewish people that Haman schemed to put all Jews to death.

Mordecai reached out to Esther advising her of Haman's plot. Esther (Esther 4:14) listened to Mordecai, and in obedience used her influence with the king "for such a time as this" to save the Jewish people.