Mordecai was the son of Jari, a descendant of Kish, a Benjamite, and cousin of Esther, whom her cared for as an adopted daughter. He resided during the Jewish captivity in the Persian metropolis of Shusan working for Ahasuerus Xeres I during the time when the king wished to disposed of Queen Vashti. Mordecai was his Persian name (see note in Daniel), probably from Marduk, patron-god of Babylonia.
It was probably when holding some office within the king’s court that Mordecai discovered by two chambermaids against his cousin’s, Esther, life. The plot was foiled, and maids were punished, but Mordecai was not rewarded (Esth. 2:5,23).
Some years later the king appointed a man named Haman as Agagite; a person in such a position was to be recognized with a bow. This Mordecai refused to do presumably because of religious reasons, a Persian custom considered idolatrous. Others think Mordecai’s refusal stemmed from the fact, which seemed more probable, that being a Jew he would not bow to an Amalekite. This aroused Haman’s indignation and he vowed revenged. He was aware or became aware of Mordecai’s ancestry, and remembering the Jewish people’s hatred against his people he resolved to exterminate them and request from the king a decree to that affect.
When hearing of this Mordecai he rent his clothes, adorned sackcloth and ashes, and went into the streets with a bitter cry. Esther, now married to the king, heard of this through servants and sent a trusted one to Mordecai to learn more. He told this servant of the decree and its intent who informed Esther. Esther took it upon herself to see the king, which was forbidden, and invited him and Hman to a banquet. She finally reveals her ancestry to the king, renounces Haman, and wins the right for her people, the Israelites, to secure weapons to defend themselves against the decree. Haman eventually hung on the gallows he had prepared for Mordecai (Esth. 6,7). After Mordecai was elevated to Haman’s position he reversed the decree against the Jews, which under imperial law the king could not do, and preserved their freedom. This is celebrated by the festival of Purim. Because he defended and helped his people Mordecai is listed within the remnant of the Jews. A.G.H.
Unger, Merrill F., Unger’s Bible Dictionary, Chicago, Moody Press, 1966, p. 738