Exodus 17:15 And Moses built an altar, and called the name of it Jehovah-Nissi.
Joshua had just won a victory in battle over the Amalekites, while Moses lifted up his arms and Aaron and Hur held them up. The holding up of his hand was an expression of worship. As long as Moses held up his hand with the rod of God, Joshua and the army prevailed. Aaron and Hur helped keep the hands up. This action was to show that it was the Lord God, not the Israelite army, that prevailed in victory over the enemy.
Then Moses’ response to God’s victory over the enemy was to worship God and thank Him. For he knew that it was not human effort, nor a stronger army, that won. It was God who prevailed. So he built an altar to express the people’s worship. The Lord gets all the credit for our salvation, and not us at all. Thus, all that’s left for us to do is build an altar.
We did not, and we cannot, win the victory or contribute to our salvation. So we build an altar of thanksgiving in our hearts and lives. Our whole life is one of worship, thanks and praise built by faith. The name of the altar is Jehovah-nissi, meaning The Lord is my Banner. And the Song of Songs says, ”His banner over me is love.” The love of God prevails and wins the daily victory over all spiritual enemies. That banner is always there, over me, for salvation, protection and blessing. Love is the strongest force in the universe. Jesus loves me; so I worship.