What is the meaning of "nor will He purify them"?

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

1. He does not purify their deeds. [Muqātil]
2. He does not praise them. [al-Zajjāj]
3. He does not purify them from the filth of their disbelief and sins. [Ibn Jarīr]