Ezekiel 23:8
Neither left she her whoredoms brought from Egypt: for in her youth they lay with her, and they bruised the breasts of her virginity, and poured their whoredom upon her. Neither left she her whoredoms brought from Egypt: for in her youth they lay with her, and they bruised the breasts of her virginity, and poured their whoredom upon her.
In prophecy a corrupt woman stands for a corrupt church, just as a pure woman stands for a true church. The two adulterous women in this portrayal are Samaria and Jerusalem, representing Israel and Judah in their doting upon the Assyrians and Babylonians. The verse teaches that Israel did not leave the whoredoms she had brought from Egypt but continued that idolatrous unfaithfulness, which had begun in her youth and early history.
The language of sexual infidelity, of bruised virginity and poured whoredom, pictures spiritual rebellion and apostasy. It shows how a people represented as a woman turns away from faithfulness to God and by that turning ensnares and corrupts others. That turning is understood against a marriage covenant, for the people were married to God and to Christ by a covenant sealed by blood and solemn vow.
Spiritual fornication is departing from that husband, from God's law and worship and precepts, to join idolatrous or false religious groups and to become friend and follower of the world. That departure is listening to the enticement of Babylon and following Satan's voice to become his bride alongside sister Babylon, taking strangers instead of her husband. It is building an eminent place at the head of every way and a high place in every street, and casting off God's precepts, which is casting off God, so that the lives of Israel and Babylon become one and Judah becomes like all the heathen.
Such unfaithfulness produces the wine of Babylon, a drunken, lascivious life lived under statutes that are not good and judgments by which they should not live. It leaves Zion drunken but not with wine and Israel fallen, to be judged after the manner of adulteresses by righteous men. Legally organizing a church to manage temporal affairs is not what the verse means by such spiritual fornication.