Mordecai just foiled an assassination plot, but we don't find Mordecai promoted as we might have expected. Haman is promoted instead (Esther 3:1). All this takes place about five years (v. 7) after Mordecai saved the king's life.

Immediately, things grow tense. King Xerxes commands that his servants at the gate bow down and pay homage to Haman. But Mordecai doesn't follow the king's command (Esther 3:2). Why not? The Old Testament law does not forbid Mordecai from bowing. Paying respects to someone doesn't necessarily mean that you are treating them as a god (see Genesis 19:1-3; Numbers 22:31; 1 Kings 1:16; 1 Samuel 24:8). Maybe Mordecai just doesn't like Haman. Or, maybe Mordecai is bitter that Haman was promoted instead of him.

Anyway, the king's servants are as puzzled as we are about Mordecai's refusal to bow. So they keep pestering him over it (Esther 3:3-4). And when Mordecai reveals that he is a Jew, they report it to Haman (v. 4). Haman's enraged response is over the top. Once he learns that Mordecai is a Jew, killing him alone isn't enough. Haman looks for a way to kill all of Mordecai's people (vv. 5-6). He wants to wipe out all the Jews in the Persian Empire.

All this because Mordecai refuses to bow down to him? What an extreme response from Haman! And why did Mordecai refuse to bow in the first place?

A likely reason can be found in their family backgrounds. Haman is described as an Agagite (Esther 3:1). Agag was the Amalekite king who was spared by King Saul. Saul's refusal to obey God by executing King Agag was a major factor that cost Saul his kingship (see 1 Samuel 15). Mordecai is a Jew from the tribe of Benjamin, the same tribe as Saul. One of his ancestors is Kish, Saul's father (Esther 2:5). So, there's bad blood between Haman's ancestors and Mordecai's ancestors. But the enmity goes back even further. In Exodus, when Israel was travelling through the wilderness on the way to the Mount Sinai, the Amalekites came out to fight against Israel (see Exodus 17:8-16). The bitterness is also between Haman's people and Mordecai's people. Indeed, God had commanded that Israel ″blot out″ the name of Amalek (Deuteronomy 25:19).

We can debate whether Mordecai's action was wise or not. But if the above reason is true, then he has taken a stand based on principle that leads to him breaking the Persian law.