Charles Spurgeon Commentary 2 Chronicles 20:4

"And Judah gathered themselves together, to seek [help] of Jehovah: even out of all the cities of Judah they came to seek Jehovah." — 2 Chronicles 20:4 (ASV)

The host of enemies was so enormous that they threatened to eat up all the land. The men of Judah could not keep them out. They would soak and storm and burn and destroy right and left. You see the great peril. What a heavy chastisement it must have been to the king to see his land thus in danger of being destroyed. But they had begun to pray.