Even God uses walls.
Then the angel who was speaking to me left, and another angel came to meet him and said to him: “Run tell that young man ‘Jerusalem will be a City without walls because of the great number of men and livestock in it”. And I myself will be a wall of fire around it, declares the Lord, and I will be it glory Within.
Perhaps we should wake up to the fact that walls do work, how could Israel exist and with withstand the attacks that it is under constantly? Israel provides the man-made walls and God provides spiritual walls of Divine protection.