Thomas Aquinas Commentary Jeremiah 8:12

"Were they ashamed when they had committed abomination? nay, they were not at all ashamed, neither could they blush: therefore shall they fall among them that fall; in the time of their visitation they shall be cast down, saith Jehovah." — Jeremiah 8:12 (ASV)

Here, he shows their shamelessness.

1. He shows a cause for shame: they are ashamed—it is as if he were saying, “They suffer punishments, of which they ought to be ashamed.” And there is a shame which brings sin .
2. He shows their shamelessness: yea, rather, they are not ashamed of shame. Above: you have had the forehead of a harlot, you would not blush (Jeremiah 3:3).
3. Their punishment: therefore, they shall fall among those that fall, as it says above (Jeremiah 6:15). When her people fell among a hostile force, and there was none to help (Lamentations 1:7).