Likutei Moharan 58:3/ליקוטי מוהר"ן נ״ח:ג׳

13. And with the power [Moshe derived] from embodying the Patriarchs, he fought against Amalek, in the aspect of “a vengeful sword to wreak vengeance for the covenant” (Leviticus 26:25). For the Patriarchs are the brit (covenant), the aspect of “I will remember My covenant with Yaakov, [My covenant with Yitzchak and also My covenant with Avraham…]” (ibid.:42). But Amalek caused their brit to be defiled, in the aspect of “they polluted you on the way” (Deuteronomy 25:18). This is the explanation of “one ascends between two”—this is the war against Amalek, of which it is said (Exodus 17:12), “Aharon and Chur supported [Moshe’s] hands, one on each side.”