Exodus 17:11

The holding up of Moses' hands signified an appeal to God in intercession. His holding up the 'rod of God' in his hand was, at the same time, an appeal to his fighting men to remember what God had already done for them. The rod was associated with many wonderful deliverances, notably that at the Red Sea, so that the sight of it would inspire the warriors with courage and hope. On both grounds one can understand how it was that the fortune of the battle corresponded to the steadfastness with which Moses held up his hands. The story illustrates the value of prayer, in particular of intercessory prayer, and, at the same time, the necessity of prayer being accompanied with believing effort. Moses praying on the hill while the people are fighting in the valley is also an emblem of Christ interceding in the heavenly places for His people struggling upon earth: see Hebrews 4:14.