“In a discourse on the nature of the Quran, Imam Ja’far al-Sadiq said,
“The Book of Allah is of four natures: al-‘ibarah, that is to say, the text, that is for the common people; al-Ishara, i.e. allusions that are for the select (khawass) al-lata’if, that is fine mysteries that are for the friends of God (awliya); and finally, al-haqa’iq, the truth which is for the Prophets (anbi’ya)”
The manifest meaning of the revelation (al-Zahir) can be understood by ordinary people (al-nas) who accept the principles of religion and observe its commands such as the daily prayers, fasting and other rituals. The inner meaning of the revelation however, can be understood only by those who have purified their hearts and those who have emptied it form anything other then God, as the Quran testifies: ” Verily, this is indeed a nobel Quran , in a Book kept hidden, which none touches except the purified”.
God the Almighty says in the Quran ” Verily, We gave the Book as an inheritance to those whom we have selected from among our servants.” It is obvious that what is meant by the Book is not only the Nobel Quran in its descended form (kitab munzal), but more importantly, the reality of the Quran that is Kitab al-maknun.
Imam Ali ibn Abi Talib asked the Prophet ” O Messenger of God! How would I spread your message to people after you?” The Prophet answered, ‘inform people of the non-manifest meaning (ta’wil) of the Quran, that is difficult for them [to understand]. Only God Knows Quran’s reality and reveals it only to the Pure (mutahharun) and those who are steadfast in knowledge (rasikhun fil’ilm)” When a man asked Imam Sadiq who the steadfast in knowledge are, he replied that “They are the progeny of Muhammad.”
In another discourse on the Quran, Imam Jafar al-Sadiq said:
‘ Verily God taught His Messenger the science of interpretation of the Quran (tanzil and ta’wil), then he taught those sciences to Ali and by God, Ali taught them to us.”
Tuhfah Yi-Abbasi: The Golden Chain of Sufism in Shi’ite Islam” by Shaykh Muhammad Ali Mu’addhdhin Sabzawari Khurasani translated by M. H. Faghfoory