Isaiah 22:8

Such an attack would be possible because the Lord would remove His defensive screen from around the city. The reason was that the people had relied on physical implements of warfare for their security rather than on Him. Evidently the "house of the forest" of Lebanon was an armory in Isaiah’s day (cf. 1 Kings 7:2-5; 1 Kings 10:17).

"The Lord is always the ultimate agent in his people’s experiences . . ." [Note: Motyer, p. 184.]