The word “Dhikr” or “Zikr” has been used in the Glorious Qur'an 292 times. “Dhikr” literally means to have something present in mind to be conscious of an object as opposed to the sub-conscious or unconscious. In the Glorious Qur'an it is always mean to be conscious of Allah or mindful of Allah and Ahle Dhikr means who are always conscious of Allah. In short Dhikr means the Glorious Qur'an, Remembrance and the Noble Messenger (s.a.w.a.s.). In all Shi'ite and some of the Sunni books, Ahle Dhikr means Ahl al-Bayt (a.s.).

Surah al-Nahl Ayah 43 says, “If you do not know ask Ahle Dhikr (the people of remembrance).

Surah al-Anbiya Ayah 7 and Ayah 10 says, “The Messengers that We have sent before you were only men to whom We had given revelation. Ask the people of al-Dhikr (family of the Noble Messenger s.a.w.a.s.) if you do not know.” “Certainly, We have revealed to you a Book in which is your good remembrance; what! Do you not understand?” Ibn Mahyar has quoted the Infallible Imam Musa al-Kazim (a.s.) regarding the explanation of this Ayah that the word remembrance or Dhikr means the obedience to the Imams , who has after the Noble Messenger (s.a.w.a.s.), the Grace and Honor of both the worlds (this world and Hereafter)

In some of the narrations they said that Ahle Dhikr meant the People of Book but in many traditions it referred to the Infallible Imams (a.s.), because the Ahl al-Bayt (a.s.) had complete and perfect knowledge of the Glorious Qur'an and also Surah al-Talaq Ayah 10-11, “Allah has sent to you a messenger who is Dhikr.” Ali bin Ibrahim and Saffar had narrated through chain of narrators that Zurara asked the Infallible Imam Muhammad Baqir (a.s.), who said, “We are Ahle Dhikr”

According to Tafsir Noor-us-Thaqalayn volume 3 pages 55-56, the Infallible Imam Muhammad Baqir (a.s.) said, “The Glorious Qur'an is Dhikr and the Ahl al-Bayt (a.s.) are “Ahle Dhikr” and all inquiries should be directed towards them.”

Similarly, according to “Ahqaq al Huq volume 3 page 482, the famous traditionalist Ibn Abbas said that Muhammad, Ali, Fatima, Hasan and Husayn are Ahle Dhikr.” (The names of twelve narrators may be seen in Tafsir-e-Namoona volume 11-Urdu translation) Ja'bir Ja'fi narrates in Tafsir-e-Tha'labi that when this Ayah of Surah al-Nahl was revealed, the Commander of the Faithful Imam Ali (a.s.) said, “We are Ahle Dhikr.”

The Ayah 43 of Surah al-Nahl relates to every aspect of material as well as spiritual aspects, hence a general rule was given to the Muslims that if they do not any thing about a particular topic then they should inquire from the expert in that field and also other people who are unaware about a subject should not interfere in that subject. The people who are truthful, selfless and just should be approached for any inquiry.

In the books of Sunni Muslims, like Tabari, Ibn Kathir, and Allusi had stressed that Ahl al-Bayt (a.s.) were the Ahle Dhikr. 

Sources used: The Glorious Qur'an (Urdu translation) by Ayatollah Nasir Makarem Shirazi

The Glorious Qur'an (English translation) by Ayatollah Agha H.M.M. Pooya Yazdi

           Hayat-al-Qulub volume 3 by Allama Muhammad Baqir Majlisi (r.a.)

           Enlightening Commentary into the Light of the Holy Qur'an