for when the speaker is known, aspects of his meaning can be understood that would not be understood if he were unknown, because knowing him reveals his customary manner of speaking. An expression conveys meaning only when the speaker’s language is known—that is, the customary usage he follows in his speech. An expression’s signification of a meaning is purposeful, intentional, and voluntary: the speaker intends the expression to convey that meaning.

When he habitually uses an expression to convey a particular meaning, that constitutes his linguistic usage. Thus, anyone who pays close attention to the Messenger’s expressions and what he intends by them comes to know his customary manner of speaking and understands aspects of his intent that others do not. Accordingly, whenever an expression from the Quran or hadith is mentioned, one should make a point of considering its parallel occurrences and what Allah and His Messenger meant by them. In this way, one comes to know the language of the Quran and hadith and the established manner in which Allah and His Messenger address His servants—the customary usage evident in that speech. If numerous parallels are then found in the speech of others, it becomes clear that this customary linguistic usage is shared and general, not peculiar to him, may Allah bless him and grant him peace; rather, it is the language of his people.

His speech must not be interpreted according to linguistic conventions that arose after him and were unknown in his speech and that of his Companions, as many people do, perhaps unaware that those conventions did not exist in his time. This is why analogy in language, even if permissible in usage, is not permissible as a basis for inference. A person may be permitted to use an expression himself for a meaning analogous to that for which they used it, provided he makes this clear—though this is disputed. But he may not take expressions whose use for particular meanings is known, assign them different meanings, and say, “They intended those other meanings by analogy with the established ones.” Rather, this is alteration and distortion.