Exodus 17:15

Moses built an altar. The building of an altar implies the offering of a sacrifice. Inasmuch as the sacrifice was offered in celebration of victory, it must have been a thank offering.

Jehovah-nissi. In naming the altar, Moses followed the example of Jacob, who had called one of his altars El-elohe-Israel (Gen. 33:20). The name of Moses’ altar meant “the Lord is my banner” and was intended to glorify God for victory over the Amalekites.

“The rod of God” (Ex. 17:9) had been held up by Moses during the battle as soldiers hold up their standards, and as soldiers follow the standard, Israel had followed the directions of God. Thus, the Lord became their standard. While in Egypt the Israelites had frequently seen the military standards of the Egyptian armies, which bore pictorial representations of their gods Amen, Ra, Ptah, Sutekh, and others, after whom their divisions were named. Giving the name “the Lord is my standard” to this altar, Moses used familiar language and at the same time called attention to the fact that the standard of the Lord was more powerful than the emblems of the Amalekites. The name “Jehovah-nissi” stands for holy boldness.