Arguably, in burning his wife, Aslam transgressed the bounds of Islam. This is because burning as a punishment is reserved for Allah, who says in the Qur’an that he could have guided everyone to the truth, but instead decided to burn some people in hell:

And if we had willed, We could have given every soul its guidance, but the word from Me will come into effect [that] “I will surely fill Hell with jinn and people all together” (32:13).

According to a hadith, burning is solely Allah’s prerogative. In a controversy over some apostates from Islam having been burned to death – not because Islam doesn’t mandate death for those who leave the religion, but because of the way it was done:

Ali burnt some people and this news reached Ibn ‘Abbas, who said, “Had I been in his place I would not have burnt them, as the Prophet said, ‘Don’t punish (anybody) with Allah’s Punishment.’  No doubt, I would have killed them, for the Prophet said, ‘If somebody (a Muslim) discards his religion, kill him’” (Bukhari 4.52.260).