Daniel 4:15

Nevertheless leave the stump of his roots in the earth, even with a band of iron and brass, in the tender grass of the field; and let it be wet with the dew of heaven, and let his portion be with the beasts in the grass of the earth:

Leave the stump of his roots in the earth, even with a band of iron and brass. The kingdom is still reserved secure for him at last, as a tree stump secure by a hoop of brass and iron from being split by the sun's heat, in the hope of its growing again (: cf. Job 14:7). Barnes refers it to the chaining of the royal maniac.