What is the meaning of "mā aṣbaruhum"?

Imām Ibn al-Jawzī (d. 597/1201) summarized the scholars' opinions in his book "Zād al-Masīr" as follows:

1. "They are so steadfast and consistent they are in doing deeds that lead them to the Fire!" [ʿIkrimah, al-Rabīʿ]
2. "How daring they are when it comes to the Fire!" [al-Ḥasan, Mujāhid] al-Kisāʾī mentioned that an Arab once said to a man who swore falsely: “How daring you are against Allah,” meaning “How bold you are.”
3. "They will remain so long in the Fire," as in the expression “How patient so-and-so is in prison,” meaning he remains there such a long time. [al-Zajjāj]
4. "What made them so daring concerning the Fire?" [Ibn al-Anbārī]