The connection between the haftorah of parshas Zachor and parshas Zachor itself is readily apparent. We read about Shaul's battle against Amalek, and his sin in sparing Agag, progenitor of Haman. Upon reflection, however, there is a second connection as well.
When Hashem informs Shmuel that Shaul is to forfeit his kingdom on account of his sin, Shmuel is deeply aggrieved. In fact, as the navi records, "vayizak el Hashem kol halayla" - Shmuel, in aguish, cries out to Hashem throughout the night. He is deeply pained at Shaul's plight, and thus he pours his heart out in an effort to intercede on Shaul's behalf.
Shmuel, of course, does not succeed. Hashem does not accept his tefilos. One would have expected Shmuel, in delivering the news to Shaul, to be somewhat reticent. And yet with the force of complete conviction, Shmuel rebukes Shaul and, without a trace of his own prior aggrievement, informs Shaul of his punishment.
Shmuel is a paragon of faith. He himself thought there was cause to be forgiving of Shaul. He thus implored Hashem to do so. And yet when Hakadosh Baruch Hu overruled him, with the conviction of pure faith, Shmuel accepted Hashem's decree as true and just.
People are perplexed by the mitzvah of eradicating Amalek, men, women, and children. Shmuel serves as a model for all generations. Not only are we to comply with ratzon Hashem, we must feel the conviction that His ratzon is true and just and be able to project that conviction.
This attitude clearly needs to be cultivated in relation to all manifestations of ratzon Hashem, whether in Torah or history.