Why did Aharon stand between the dead and the living?
Rashbam To prevent the Malach ha'Maves from crossing and continuing to kill.
Seforno: To cure those who had already been affected by the plague and were ill. 1
Targum Yonasan: To Daven that the plague should cease.
?Vaya?amod bein ha?Meisim u?Vein ha?Chayim?. Why does the Torah insert the word ?Bein? twice?
R. Bachye: Because had it written ?Bein ha?Meisim ve?ha?Chayim?, it would have implied that Aharon stood in between the dead and the living, when in fact he stood between two groups of dead and living. 1
R. Bachye (citing the Tanchuma): The Pasuk also implies that, before Aharon came with the Ketores, the Mal?ach was killing the living and ravaging the dead, and that, after he arrived, the living remained alive and the dead, intact.
What did Aharon do to stop the plague?
Rashi: After scattering the Ketores between the dead and the living, he seized the Mal'ach ha'Maves and convinced him that, despite the fact that Hashem had sent him to destroy, Moshe, who only carried out the instructions of Hashem, had sent him to stop the plague. 1
By going back to Moshe and asking him - as implied by Pasuk 15 "Vayashav Aharon el Moshe ... ". See Rashi and R. Bachye.
What are the connotations of ?Vate?atztar ha?Mageifah??
Seforno: It means that nobody else became affected by the plague.
