2 Kings 17:9

9 The Israelites secretly did things against the LORD their God that were not right. From watchtower to fortified city they built themselves high places in all their towns.

Read 2 Kings 17:9 Using Other Translations

And the children of Israel did secretly those things that were not right against the LORD their God, and they built them high places in all their cities, from the tower of the watchmen to the fenced city.
And the people of Israel did secretly against the LORD their God things that were not right. They built for themselves high places in all their towns, from watchtower to fortified city.
The people of Israel had also secretly done many things that were not pleasing to the LORD their God. They built pagan shrines for themselves in all their towns, from the smallest outpost to the largest walled city.

What does 2 Kings 17:9 mean?

John Gill's Exposition of the Bible
2 Kings 17:9

And the children of Israel did secretly those things that were
not right against the Lord their God
As being partly conscious to themselves that they were not right, and ashamed to commit them openly; and partly as foolishly imagining, that, being done privately, they were not seen and observed of God, having imbibed some atheistical notions of him, that he was not omniscient, or saw not, and had forsaken the earth; or they "covered" F7 these actions of theirs under reigned and plausible pretences, that what they did they were obliged to by their kings, and with political views, and that they worshipped the true God in the calves; but these were coverings too thin not to be seen through:

and they built them high places in all their cities, from the tower of
the watchmen to the fenced city;
not content with those built in former times, they built new ones; and these not in their metropolis only, but in all the cities of the kingdom; and not in large cities only, but in every town and village between one fortified city and another; even wherever there was a watch tower erected, either for shepherds to watch their flocks, or for keepers of gardens, orchards, and vineyards, to watch the fruits of them, that they were not taken away.


FOOTNOTES:

F7 (wapxy) "occultaverunt", Montanus, Vatablus, Grotius; "palliaverunt", Piscator.
California - Do Not Sell My Personal Information  California - CCPA Notice