Idolatry

Ezekiel 23
1 The word of the LORD came again unto me, saying,
2 Son of man, there were two women, the daughters of one mother:
3 and they committed whoredoms in Egypt; they committed whoredoms in their youth: there were their breasts pressed, and there they bruised the teats of their virginity.
4 And the names of them were Aho'lah the elder, and Ahol'ibah her sister: and they were mine, and they bare sons and daughters. Thus were their names; Samaria is Aho'lah, and Jerusalem Ahol'ibah.
30 I will do these things unto thee, because thou hast gone a whoring after the heathen, and because thou art polluted with their idols.

From John Gill's Exposition of the Entire Bible:
In this chapter the idolatries of Israel and Judah are represented under the metaphor of two harlots, and their lewdness. These harlots are described by their descent; by the place and time in which they committed their whoredoms; by their names, and which are explained.

This is a Tough Chapter
I'll pass on further quotes. A strange mix of sin, lust, idolatry. Here, Judah and Israel are the harlots. Compare to the whore of Babylon in Revelations.