10:5,6
Beth-Aven means “House of Iniquity” and is a polemical term used by Hosea to refer to Bethel, where this idol was originally set up, though it would be carried off to Assyria. An example of a similar term today could be referring to the Episcopal Church of America as the Apostate Church of America. Why the trembling? Maybe the people feared that it would be carried away, and then they wondered where their help would come from (though, of course, it never actually came from the calf-idol!). They would all moure, people and priests alike, when it was taken into exile. All this would bring shame upon Israel.
10:7,8
The high places had been set up as places to worship idols, the king was complicit in all this, ruling a rebellious kingdom. Both would be destroyed. The king would be swept away, the high places destroyed. Note that Israel (and Judah) had been told on numerous occasions not to set up high places, and having set them up, to totally destroy them. She had failed to do so, so God would do it Himself. We either fulfil God’s commands, or He will fulfil them Himself.
The high places would become utterly desolate. The cry to the mountains to fall upon them is echoed in Revelation. (Rev 6:16).