Jesus answered every temptation with, "It is written." The Word of God is the sword of the Spirit (Ephesians 6:17). It is the only spiritual weapon that we have.
Since Jesus was the Word of God (John 1:1), anything he would have spoken would have been the Word. He could have said "scat" and the devil would have had to go. He quoted the written Word three times.
This gives us great assurance that the written Word of God is sufficient for us. Jesus, facing of the greatest temptations that satan had to offer, didn't need to say anything else.
It is likely that when Jesus returns to this earth and destroys His enemies, He will just speak the Word that has already been given. No wonder satan tries to keep us from studying and knowing God's Word. Even our good works will hurt us if they keep us from really knowing the scriptures.
God has given us this mighty weapon, His Word! When we speak the Word in faith, hell shakes. Satan and his demons have already experienced what the Word can do. They know its power. We need to know it, too.
