Exodus 17:13

וְהָיָה כַּאֲשֶׁר יָרִים מֹשֶׁה יָדוֹ וְגָבַר יִשְׂרָאֵל וְכַאֲשֶׁר יָנִיחַ יָדוֹ וְגָבַר עֲמָלֵֽק

And it came to pass, when Moses held up his hand, that Israel prevailed; and when he let down his hand, Amalek prevailed.

וִידֵי מֹשֶׁה כְּבֵדִים וַיִּקְחוּ־אֶבֶן וַיָּשִׂימוּ תַחְתָּיו וַיֵּשֶׁב עָלֶיהָ וְאַהֲרֹן וְחוּר תָּֽמְכוּ בְיָדָיו מִזֶּה אֶחָד וּמִזֶּה אֶחָד וַיְהִי יָדָיו אֱמוּנָה עַד־בֹּא הַשָּֽׁמֶשׁ

But Moses’hands were heavy; and they took a stone, and put it under him, and he sat thereon; and Aaron and Hur stayed up his hands, the one on the one side, and the other on the other side; and his hands were steady until the going down of the sun.

וַיֹּאמֶר יְהוָה אֶל־מֹשֶׁה כְּתֹב זֹאת זִכָּרוֹן בַּסֵּפֶר וְשִׂים בְּאָזְנֵי יְהוֹשֻׁעַ כִּֽי־מָחֹה אֶמְחֶה אֶת־זֵכֶר עֲמָלֵק מִתַּחַת הַשָּׁמָֽיִם

And the LORD said unto Moses: ‘Write this for a memorial in the book, and rehearse it in the ears of Joshua: for I will utterly blot out the remembrance of Amalek from under heaven.’

וַיִּבֶן מֹשֶׁה מִזְבֵּחַ וַיִּקְרָא שְׁמוֹ יְהוָה נִסִּֽי

And Moses built an altar, and called the name of it Adonai-nissi.