What is the ruling on the saying: "If the killer had been patient with the victim, he would have died on his own"?

The slain dies at his appointed time, and this is a predetermined matter that cannot be changed. The statement that the slain would not have died had he not been killed is incorrect, for Allah's decree preceded his death by this cause and no other. Assuming the absence of this cause is an assumption contrary to what is decreed, and it is impermissible to assert what would have happened had he not been killed.