Isaiah 8:7
Now therefore, behold, the Lord bringeth up upon them the waters of the river, strong and many, even the king of Assyria, and all his glory: and he shall come up over all his channels, and go over all his banks: Now therefore, behold, the Lord bringeth up upon them the waters of the river, strong and many, even the king of Assyria, and all his glory: and he shall come up over all his channels, and go over all his banks:
The waters of the river are a symbol of nations and their shifting tides of power, representing great movements and changes in national power. The king of Assyria and all his glory is pictured as a mighty flood that comes up over all its channels and goes over all its banks to overrun the land. In its historical setting, Judah under Ahaz appealed to Assyria for help against danger, and that reliance brought the very danger it sought to escape, giving temporary relief but exposing Judah to Assyrian greed and threat.
The image of waters stealing upon people and going over their heads means overwhelming trouble coming from unwise plans, with difficulties ahead that are not now discerned flooding over those involved. Applied specifically, setting book prices too low will bring financial embarrassment that floods over those responsible and robs the publishing work of vital power to carry forward and reproduce publications.
The verse therefore calls for being guarded by going over matters carefully and critically with due deliberation and prayer and by rectifying wrong calculations before the waters rise.