Du’ād was not a Mu‘tazilī; rather, he was a Jahmī who denied the attributes. The Mu‘tazilah also deny the attributes, so the attribute-denying Jahmiyyah are a broader category than the Mu‘tazilah. When Burghūth argued against Ahmad that, if Allah spoke and speech inhered in Him, He would be a body—which is denied of Him—Ahmad and others like him among the early generations knew that these expressions introduced by speculative theologians, such as “body” and others, were denied by some in order to deny what Allah Most High and His Messenger had affirmed, and affirmed by others in order to affirm what Allah and His Messenger had denied.
The first approach is that of the Jahmiyyah, including the Mu‘tazilah and others. They deny that Allah is a body so that Muslims will imagine that their purpose is to declare Him free of imperfection. What they mean, however, is that Allah will not be seen in the Hereafter; that He did not speak the Quran or anything else, but instead created speech in something other than Himself; and that He has no knowledge, power, life, or other attributes inhering in Him.
Imam Ahmad said in the introduction to his Refutation of the Jahmiyyah and the Heretics:
“Praise be to Allah, who, in every interval between messengers, has preserved a remnant of people of knowledge who call those who have gone astray to guidance and patiently endure the harm they inflict. Through Allah’s Book they bring the dead to life, and through His light they give sight to the blind. How many a victim of Satan they have revived, and how many a lost wanderer they have guided! How good their effect upon people, and how evil people’s treatment of them! They defend Allah’s Book against the distortions of extremists, the false claims of the purveyors of falsehood, and the misinterpretations of the ignorant—those who have raised the banners of religious innovation and let loose the reins of discord.