John Gill, on Ezek 16:56

Before thy wickedness was discovered,.... By the punishment of it, by the judgments of God brought upon them; then they were humbled, who before were proud and haughty; and might speak and think of the vengeance of God on Sodom, which before they made no mention of. It is a sad thing only to know sin, and to have it discovered only by the punishment of it: as at the time of thy reproach of the daughters of Syria, and all that are round about her, the daughters of the Philistines; this seems to refer to the times of Ahaz, when the Syrians smote the men of Judah; and carried many of them captive; and the Philistines invaded the cities of the low country, and southern parts of Judah, and took many of them, Ch2 28:5; at which time the wickedness of the Jews was discovered; and it was a plain case they had sinned against the Lord, by his suffering their enemies to come upon them, and prevail over them; which was to their reproach. The Syrians reproached them, and so did the Philistines: which despise thee round about; they spoiled and plundered them on all sides; and treated them with scorn and contempt, who before were formidable and terrible to them: thus it is with a people when they are left of God, they are despised by men.