Thomas Aquinas Commentary Lamentations 4:6

"For the iniquity of the daughter of my people is greater than the sin of Sodom, That was overthrown as in a moment, and no hands were laid upon her." — Lamentations 4:6 (ASV)

Here, the author magnifies the punishment by comparing it to that of Sodom; is made greater, for its greatness is shown in the punishment. The fault was greater due to their ingratitude and the desecration of holy things, and the punishment was greater because it was more long-lasting. As Scripture says, Your sister Sodom herself, and her daughters, have not done as you have done, and your daughters (Ezekiel 16:48), and, It shall be more tolerable for the land of Sodom in the day of judgment, than for you (Matthew 11:24).

This is also seen in Job: If he scourge, let him kill at once, and not laugh at the pains of the innocent (Job 9:23). In the Gloss, it is noted that, morally, this concerns the sin of simulation, which is a greater sin than that of the men of Sodom. Paschasius Radberchus, Expositio in lamentationes (Corpus Christianorum Continuatio Mediaevalis 85), 4.864.

This seems contrary to what is said in Isaiah: they have proclaimed their sin as Sodom (Isaiah 3:9), upon which the Gloss comments, the second plank after shipwreck is to hide the sin.Jerome, Commentarii in Isaiam . Cf. In IV Sent. d. 14, q. 1, a. 2, qa. 4, ad 3. The first plank in the metaphor is the ship itself, but the second plank can still bring one to safety; thus, metaphorically, after the shipwreck of sin, one can still reach safety by means of the shame of the sin that leads to penance.

To this, it is replied that sinning secretly is a mitigating circumstance. However, the sin of simulation is more vicious when, by this means, we seek to deceive others and gain glory for ourselves. Certainly, this sin is said to be greater not in itself, but with regard to the effect of its deception.

Alternatively, it is greater with regard to the subject matter of the sin. This is because simulation concerns spiritual things. In this realm, one who presents a falsehood is guiltier than one who makes counterfeit money, as the Philosopher says.Aristotle, Nicomachean Ethics 7.7, 1150a27.