The Validity of the Commentary of the Prophet and the imams

From an indication in the Qur'an itself, the commentary of the Prophet and the Imams, (as discussed in the previous sections), is established as being absolutely true. Authentication of the sayings of the Prophet and the Imams is clearly established by the existence of fully trustworthy chains of transmissions. A tradition may not, however, be recognized as totally acceptable if it has been transmitted by one chain of narration only.
The validity of the tradition may be disputed amongst the Muslim Scholars of Commentary: amongst the Sunni's a tradition of a single chain of transmission, classified in their terms as sahih (sound), must be accepted and acted upon; among the Shi'ite scholars a tradition with a single undisputed chain of transmission is also accepted as a proof.
However, in the laws of the shari'ah it is not valid and must be investigated and checked before use as a proof.
Author's Note: The previous section has been specifically about the use of commentary or explanation in order to arrive at the true meaning of a verse. This includes study of the literal meanings and those hidden in metaphor. It does not include an explanation or a discussion of the linguistic and literal aspects or the science of Qur'an recitation since these do not affect the meaning.