“And I sought for a man among them who would make up the fence and stand in the gap before me for the land, that I should not destroy it, and I found none.”
This was the final dreadful fact that when God sought for one man from all these described who could stand up and plead for the land with God, who could stand between Him and those who were to be judged, there was not one. In general the land was empty of righteous men. True there was Jeremiah His prophet. True there were those who assisted him and sought to protect him, and there were as ever the remnant of the righteous. But of the total recognised leadership, with the recognised status to act, none was fit or ready. There was none who was influential enough to stand in the gap, intercede for the people and bring them with him as Moses had once done (Numbers 16:45-48; Exodus 32:31-32).
This suggestion does not contradict His words in Ezekiel 14:12-23. There the argument was that the people were so wicked that even those three righteous men present among them would not stem God's judgment. Here He is saying the same thing in another way, that in fact there was not one who was fit to act as an intercessor. (He is not saying that one could have succeeded, but that there was not even one who could try. Compare Ezekiel 13:5).
“These things will be done to you, for you have gone a-whoring after the heathen, and because you are polluted with their idols.”
And all this was to come on her because she had turned her back on her faithful Protector and had looked to other less worthy objects of desire, and given them her love and devotion. They had become polluted with their idols.