Midras Mazmur 20:8: Mekhilta DeRabbi Yishmael, Midrash Tanchuma, Shemot Rabbah & Bereshit Rabbah

And thus did David say to Goliath (I Samuel 17:45) "You come to me with a sword, a spear, and a javelin — but I come to you with the name of the L–rd of hosts, the G–d of Israel." And it is written (Psalms 20:8-10) "These with chariots and these with horses; but we, in the name of the L–rd our G–d will call. They knelt and they fell, but we rose and gained courage. O L–rd, save! The King will answer us on the day that we call."

"the L–rd is His name": It is with His name that He wars, and He has no need of any of these (military) appurtenances. And thus did David say (I Samuel 17:95) "You come to me with sword, and spear, and javelin; but I come to you with the name of the L–rd of hosts, etc." And (Psalms 20:8) "These with chariots and these with horse, but we with the name of the L–rd our G–d, etc." And thus did Assa say, viz. (II Chronicles 14:10) "And Assa called out to the L–rd his G–d and said: O L–rd, there is none besides You, etc."

"the L–rd is His name": It is with His name that He wars, and He has no need of any of these (military) appurtenances. And thus did David say (I Samuel 17:95) "You come to me with sword, and spear, and javelin; but I come to you with the name of the L–rd of hosts, etc." And (Psalms 20:8) "These with chariots and these with horse, but we with the name of the L–rd our G–d, etc." And thus did Assa say, viz. (II Chronicles 14:10) "And Assa called out to the L–rd his G–d and said: O L–rd, there is none besides You, etc."