Sufis and devout worshippers attain through their spiritual discipline and religious devotion in apprehending realities and having them unveiled to them, to the point that they use this as a standard for judging what the revealed Law has brought. The reason for this was that, through his intelligence and sincere pursuit, he had recognized the inconsistencies in the approach of speculative theologians and philosophizing thinkers. Allah had granted him faith in broad outline—as he himself related—and he began yearning for a detailed understanding of that outline. In the words of the spiritual masters and Sufis, he found something closer to the truth and more firmly grounded than the discourse of philosophers and speculative theologians. His assessment was correct. Yet he had not learned of the prophetic inheritance of knowledge and spiritual states possessed by the foremost members of the Muslim community, or of the knowledge and worship attained by the earliest forerunners, through which they achieved unveilings of knowledge and acts of devotion that those others had not attained.

He therefore came to believe that a detailed understanding of that outline could be attained through that path alone, since he knew no other path. The distinctively Sunni, prophetic path had been closed to him by his limited knowledge of it and by the specious arguments he had adopted from philosophizing thinkers and speculative theologians, who thereby stood between him and that path. For this reason, he frequently condemned these barriers and the path of knowledge. But this concerned only the knowledge he had pursued, which had veiled him from truly following the prophetic message. It is not knowledge at all, but merely philosophical and theological doctrines. As the early Muslim generations said:

“Knowledge of speculative theology is ignorance.”

And as Abū Yūsuf said:

“Whoever seeks knowledge through speculative theology becomes a heretic.”