I've always liked this image of Moses demonstrating Israel's total reliance on God in this kind of symbolic prayer with Joshua demonstrating their total reliance on God by actually going out there and fighting. Both men were being obedient. Beyond that, I really love the reminder that even the greatest leaders need others to hold their arms up -- Aaron and Hur were with him and saw his need and joined him in the work.
This morning I was looking again (as I was finishing up the last couple of questions for BSF so I would be ready for small group tonight) at the last verses where Moses sets up a memorial of this event and names it "The Lord is My Banner." (I had to look in the KJV to find "Jehovahnissi" and then NLT to find "Yahweh-nissi." Bible Gateway sure makes this kind of thing easier.)
The thing is, I don't readily know that that means. I don't have a banner in my day to day life, so I had to think about it. Now, what I'm about to say will totally offend someone and I assure you that is not my intent.
As I considered what this means for me -- what application I can draw from this image of God as my Banner -- I was suddenly thankful for the Harry Potter books which are set in a boarding school that is divided into four houses and each house stands under a banner. That banner is more than a flag or a shield or a crest -- it is a long-established reputation and identity, a sign of belonging and a means of definition, a point of unity and a declaration of intent.
So, if God is my Banner, that means I am not only defined by Him, I am protected by Him. I wear His colors. I submit myself -- my individual desires and comfort -- to His mission.
In that context, the rather silly song we used to sing at camp has a little more something to it-- "Jesus is the Rock of my salvation. His banner over me is love."