Exodus 17:7-9

Young's Literal Translation

⁷ and he calleth the name of the place Massah, and Meribah, because of the `strife' of the sons of Israel, and because of their `trying' Jehovah, saying, `Is Jehovah in our midst or not?'

⁸ And Amalek cometh, and fighteth with Israel in Rephidim,

⁹ and Moses saith unto Joshua, `Choose for us men, and go out, fight with Amalek: to-morrow I am standing on the top of the hill, and the rod of God in my hand.'