The events we read in chapter 3 took place four years after Esther became queen (cf. 2:16; 3:7).
Agag was the name of an area in Media that had become part of the Persian Empire.54However, Agag was also the name of the Amalekite king whom Saul failed to execute (1 Sam. 15:8; cf. Num. 24:7). By mentioning both Kish, Saul's father, and Agag, the Amalekite king, the writer may have been indicating that both men were heirs to a long-standing tradition of ethnic enmity and antagonism.55
Mordecai's refusal to bow before Haman (v. 2) evidently did not spring from religious conviction (cf. 2 Sam. 14:4; 15:28; 1 Kings 1:6) but from ancient Jewish antagonism toward the Amalekites.56Mordecai did not have to worship Haman (cf. Dan. 3:17-18). Not even the Persian kings demanded worship of their people.57Nevertheless Ahasuerus had commanded the residents of Susa to honor Haman (v. 3). Probably people knew that Mordecai was a Jew long before his conflict with Haman arose (v. 4).
"While the fact that he was a Jew (4) would not preclude his bowing down, the faith of the exiles tended to encourage an independence of judgment and action which embarrassed their captors (Dn. 3; 6)."58
Haman might have been successful in getting Mordecai executed. However when he decided to wipe out the race God chose to bless, he embarked on a course of action that would inevitably fail (cf. Gen. 12:3).