Unlike fabric flags, ancient banners were usually made out of wood or metal shaped into various figures or emblems that could be fastened to a bare staff or long pole. Most banners were planted on a high hill to serve as a rallying point for the troops before, during, and after the battle. When Moses held up the staff of God during the battle with the Amalekites he was appealing to God's power. He thus created a memorial of God's protection and power during the Israelites' first battle after leaving Egypt.
We may not want warfare, but it is there nonetheless. But the victory has been won. Look up to the standard of the cross. We cannot win the battle in the flesh. The answer is not to try harder. We cannot put our will against our flesh - We must, however, submit our will to the Holy Sprit.
Jn.3:14-15 - And as Moses lifted up the serpent in the wilderness, even so must the Son of man be lifted up: That whosoever believeth in him should not perish, but have eternal life.
Psalm 60:4 - Thou hast given a banner to them that fear thee, that it may be displayed because of the truth.
Song of Solomon 2:4 - He brought me to the banqueting house, and his banner over me was love.