Allah came out to his Companions while they were debating divine decree. One man was saying, ‘Did Allah not say such-and-such?’ and another was saying, ‘Did Allah not say such-and-such?’ His face looked as though pomegranate seeds had been crushed upon it. He said, ‘Is this what you were commanded to do? Those before you perished precisely because of this: they set parts of Allah’s Book against one another. Allah’s Book was revealed so that its parts would confirm one another, not contradict one another. Consider what you have been commanded to do and do it, and what you have been forbidden to do and avoid it.’” This is the hadith, or words to that effect.

Likewise, he said:

“Disputation concerning the Quran is disbelief.”

Likewise, al-Bukhārī and Muslim narrated in their two Sahīh collections from ‘Ā’ishah:

“The Prophet recited His words: ‘It is He who has sent down to you the Book. In it are verses that are clear—they are the foundation of the Book—and others that are ambiguous. As for those in whose hearts is deviation, they follow what is ambiguous in it, seeking discord and seeking its interpretation.’ The Prophet then said, ‘When you see those who follow what is ambiguous in it, they are the ones Allah has named, so beware of them.’”

As for the Book or the Sunnah forbidding knowledge of matters that rightly belong to the fundamentals of Allah’s religion, this cannot be the case—unless, of course, we prohibit some of this in certain circumstances, such as addressing someone with something beyond his understanding, thereby causing him to go astray. This accords with the saying of ‘Abdullāh ibn Mas‘ūd:

“No man relates to people something beyond their understanding without it becoming a trial for some of them.”

And with the saying of ‘Alī, may Allah be pleased with him:

“Speak to people about what they understand, and leave aside what they find unfamiliar. Do you wish Allah and His Messenger to be disbelieved?”

Or, for example, uttering a truth that entails harm