Sh'mot (Exodus) 17:8-16
8 And Amalĕq came and fought with Yisra'ĕl in Rephiḏim.
9 And Mosheh said to Yahoshua, "Choose for us men and go out, fight with Amalĕq. Tomorrow I am stationing myself on the top of the hill with the rod of Elohim in my hand."
10 And Yahoshua did as Mosheh said to him, to fight with Amalĕq. And Mosheh, Aharon, and Ḥur went up to the top of the hill.
11 And it came to be, when Mosheh held up his hand, that Yisra'ĕl prevailed. And when he let down his hand, Amalĕq prevailed.
12 But Mosheh's hands were heavy, so they took a stone and put it under him, and he sat on it. And Aharon and Ḥur supported his hands, one on one side, and the other on the other side. And his hands were steady until the going down of the sun.
13 And Yahoshua defeated Amalĕq and his people with the edge of the sword.
14 And יהוה said to Mosheh, "Write this for a remembrance in the book and recite it in the hearing of Yahoshua, that I shall completely blot out the remembrance of Amalĕq from under the shamayim."
15 And Mosheh built an altar and called its name, יהוה Nissi,
16 for he said, "Because a hand is on the throne of Yah, יהוה is to fight against Amalĕq, from generation to generation."