{And those who disbelieved, so woe to them.} The interpretation of al-Hasan: that 'ta'san' (woe/doom) is a curse from Allah upon them, and it is an Arabic word.

Muhammad said: It was said that the meaning of (ta'san lahum) is: 'let there be distance for them' (i.e., may they be cast away). They said: 'ta'isa al-rajulu' (the man has fallen into misfortune/been undone). There is another linguistic form: 'ta'asa' with a fathah on the 'ayn. And I say 'at'astuhu' (I caused him to fall into misfortune), meaning: I made him wretched. 'Ta'san' is in the accusative case, based on the meaning: 'May Allah cause them to fall into misfortune.'

{And He has misguided their deeds.} He has nullified whatever was good among them.