The translator's mastery of the language used by the narrator is crucial. If an Arab is among non-Arabs and does not understand the language of those from whom he transmits, he will not gain certainty through transmission.

The Nature of Knowledge Gained Through Tawatr: Most Usuliyyun (jurists and theologians) hold that knowledge gained through tawatr is necessary knowledge, which is acquired directly in the soul without deliberation. A person cannot resist it. When tawatr occurs, the soul is compelled to accept the knowledge of the truthfulness of what has been transmitted, by custom.

It has been narrated from some Usuliyyun, such as Abu al-Qasim al-Ka'bi and Abu al-Husayn al-Najar from the Mu'tazila, and al-Juwayni from the Ash'aris, that knowledge gained through tawatr is acquired, and is not obtained in the soul except through inference and the arrangement of premises. This is like arranging the knowledge that the reported matter is a tangible thing, and that the reporters are a group who have no reason to conspire to lie. And that what is like that cannot be a lie. Thus, knowledge of the truthfulness of what is transmitted through tawatr arises from the arrangement of these premises, through inference.

As for al-Ghazali, he considered this knowledge to be necessary, but he elaborated on it in a way that suggests it is not of the first degree of necessity, which is only achieved in primary knowledge, which is acquired in the soul without any apparent or imagined intermediary. This is like the knowledge that the eternal cannot be created, and the existent cannot be non-existent. However, knowledge through tawatr is not achieved in the soul except by establishing two premises: the first is that the narrators, despite their differing opinions, have no common factor that would lead them to lie. The second is that they have agreed to report on an event. Thus, when the soul perceives these two premises, knowledge of the truthfulness of the report is achieved. This is a lesser degree of necessity than the degree of primary knowledge, and it is as if it is a degree between primary knowledge and inferential knowledge.