Tafsir of Saba' 34:42

"The matter on that Day belongs to Allah alone; no one possesses therein any benefit or harm for anyone."

This is because that abode is a place of reward and punishment, and the One who rewards and punishes is Allah. Thus, its state is contrary to the state of the worldly life, which is an abode of obligation (taklif), where people are left to themselves, harming and benefiting one another.

The intended meaning is: there is no one who harms or benefits on that Day except Him alone.

Then, He mentions His punishment of the wrongdoers with His saying: "And We will say to those who did wrong," which is conjoined to "possess no."

"And when Our verses are recited to them as clear evidences, they say, 'This is not but a man who wishes to avert you from that which your fathers were worshipping.' And they say, 'This is not but a lie invented.' And those who disbelieve say of the truth when it has come to them, 'This is not but obvious magic.'"