to people in the matters over which they differ, as the Most High says:
“ mankind was one community; then Allah sent the prophets as bearers of good tidings and warners, and sent down with them the Book in truth to judge between people concerning that over which they differed.” Al-Baqarah: 213.
This is like judging, by the Book, between all other nations concerning their disagreements over meanings that they express according to their own terminology and customary usage. This requires knowledge of the meanings of the Quran and Sunnah, and knowledge of the meanings these people intend by their expressions. These meanings must then be compared with those meanings, so that what agrees and what conflicts may become clear.
As for the questioner’s statement:
“If this is said to be permissible, on what grounds, when we have understood from him, may Allah bless him and grant him peace, that discussion of certain questions is prohibited?”
[Response to the second question]
The response is:
The need to clarify the intended meaning and draw distinctions has already been explained in answering the question. Whatever truly belongs to the foundations of the religion with which Allah sent His Messenger cannot under any circumstances be prohibited. This is unlike what is called ‘the foundations of religion’ but does not truly constitute its foundations, whether in its proofs or its doctrinal questions; or what constitutes the foundations of a religion that Allah did not prescribe, but was instead prescribed by those who instituted religious practices for which Allah gave no permission.
As for the prohibition by the Prophet mentioned by the questioner, the Quran and Sunnah prohibit a number of things:
[Matters prohibited by the Quran and Sunnah]
Among them is speaking about Allah without knowledge, as in the words of the Most High:
“Say: My Lord has only forbidden shameful deeds, whether committed openly or in secret, sin, unjust aggression, associating with Allah that for which He has sent down no authority, and saying about Allah what you do not know.”
[Al-Aʿrāf: 33]
And His words:
“Do not pursue that of which you have no knowledge.”
[Al-Isrāʾ: 36].