The foremost friends of Allah in this community are Abū Bakr and Umar—may Allah be pleased with them both—and the foremost recipient of inspiration in this community was Umar, as indicated by the hadith and by the other hadith:

“Allah has firmly established the truth upon Umar’s tongue and in his heart.”

Nevertheless, al-Siddīq (the Truthful) was superior to him, for al-Siddīq drew only from the light of the prophetic message, not from his own unveilings or inward communications. What the Messenger brought is protected from error; no error is allowed to persist in it. By contrast, the inward communications and direct perceptions experienced by people devoted to the spiritual life contain both truth and error. Only through the light of prophethood can their truth be distinguished from their error. Thus Umar would weigh whatever came to him against the prophetic message: whatever agreed with it he accepted, and whatever contradicted it he rejected.

One of the spiritual masters said, in words to this effect:
“We have been guaranteed protection from error in what the Quran and the Sunnah have brought, but we have not been guaranteed protection from error in unveilings.”

Abū Sulaymān al-Dārānī said:
“A subtle insight of the kind experienced by the spiritual masters may pass through my heart, but I do not accept it without two witnesses: the Quran and the Sunnah.”

Abū Amr Ismā‘īl ibn Nujayd said:
“Every spiritual tasting—or every inward experience—that is not attested by the Quran and the Sunnah is invalid.”

Al-Junayd ibn Muhammad said:
“This knowledge of ours is bound by the Quran and the Sunnah. Whoever has not read the Quran and recorded hadith is unfit to speak about our knowledge.”

Sahl also said:
“O seekers, never abandon the written texts, the black ink on white pages. No one has abandoned them without falling into heresy.”