Upon this the king, a Phalaris in everything and filled with madness … : For Phalaris see the comments on verse 20. The writer is saying that Philopator was acting just like Phalaris would have acted. Filled with madness means the king was so angry that he could not control himself; he was acting insane. We may begin this verse with “When the king heard this, he went into a furious rage, like the cruelest king who had ever lived…” or “… he became violently angry, just like….”

Took no account of the changes of mind which had come about within him for the protection of the Jews: The king completely disregarded the two times before that he had changed his mind and had decided to protect the Jews instead of kill them.

And he firmly swore an irrevocable oath that he would send them to death without delay, mangled by the knees and feet of the beasts: Previously the king had simply given orders to kill the Jews. This time he bound himself with a solemn oath that is irrevocable—that cannot be taken back—that he would have the elephants kill the Jews. He even detailed the parts of the elephants’ bodies that would crush the Jews to death. Death is literally “Hades” (Revised Standard Version footnote), which is the place of the dead.

Alternative models for this verse are:

• When the king heard this, he went into a furious rage [or, became very angry], like the cruelest king who had ever lived.* Twice he had changed his orders and protected the Jews. But now he forgot all about that. He swore that this time he would have the Jews trampled to death by the elephants, and said that this oath [or, promise] could not be changed.
* The Greek text refers to King Phalaris, who had ruled in Sicily four hundred years earlier.

• … He said, “I swear with an oath [or, promise] that cannot be changed, that I will have the elephants trample the Jews to death [crushing them with their knees and feet].”

Quoted with permission from Bullard, Roger A. and Hatton, Howard A. A Handbook on 3-4 Maccabees. (UBS Helps for Translators). Miami: UBS, 2018. For this and other handbooks for translators see here.