The other question the school was formed to answer is what to do with the language scripture uses about God. The Quran speaks of the hand of God, the face of God, God seated on the throne, and of God hearing and seeing. Read one way this gives God a body. Read the other way, the way the Mutazila took it, the attributes dissolve into the essence and the words become figures of speech.
The Ashari formula is bila kayfa, without asking how. The attributes are affirmed as real and as distinct from the essence, and the manner is left alone: the texts are accepted as they stand, and what they mean in detail is not something a human mind is equipped to specify. The point is a boundary rather than an evasion. Affirming the words keeps revelation from being explained away, and refusing the how keeps God from being made into a large man.
The same instinct governs the school position that the Quran is uncreated. The generation of scholars before al-Ashari had lived through the mihna, the inquisition in which the Abbasid state tried to compel judges and scholars to profess that the Quran was created, so the question carried more than metaphysics with it. The school held that the Quran as the speech of God is an eternal attribute, while the ink, the paper and a particular recitation are created things.
The position travelled through institutions as much as through argument. It became the theology taught alongside Shafii and Maliki law in the madrasa system, and the endorsement of al-Ghazali carried it further than any polemic could.