Matthew 18:6

but whoever ensnares one of these little ones that believe in me, it were better for him that a millstone were hung about his neck, and that he were drowned in the depth of the sea.

Revelation 18:21

And a mighty angel took up a stone like a great millstone, and threw it into the sea, saying: Thus, with violence shall Babylon, that great city, be thrown down, and shall be found no more at all.

Treasury of Scripture Knowledge

Summary

The depths have covered them: they sank into the bottom as a stone.

Depths

Bible References

Depths

Matthew 18:6
but whoever ensnares one of these little ones that believe in me, it were better for him that a millstone were hung about his neck, and that he were drowned in the depth of the sea.

They

Revelation 18:21
And a mighty angel took up a stone like a great millstone, and threw it into the sea, saying: Thus, with violence shall Babylon, that great city, be thrown down, and shall be found no more at all.