Extent of obligatory knowledge

Question :

I would like to know the extent of the knowledge that it is conditional to know before practicing Da‘wah (calling to Islam). What type of knowledge should be studied and how can it be obtained? Which books should be studied in particular, please let me know their names, and whether it is stipulated that they should be taught by a scholar or not? How do we begin calling others to the Truth? Please explain the method clearly, bearing in mind that I am a student in the Faculty of Medicine, which requires that I spend a lot of time and effort in studying. I hope that you will answer me in detail, not just a summary, so anyone will be able to understand it.


Firstly: It is obligatory on every Muslim to convey the knowledge they have, whether it is much or little to those who do not know it, without any limitations on time or the amount of knowledge. It is necessary for them to explain what they know and convey it, and this becomes obligatory if there is no one else who can do it. This is emulating the example of Prophet (peace be upon him) and acting upon the Hadith narrated by Ahmad, Al-Bukhari, and Al-Tirmidhi, on the authority of ‘Abdullah ibn ‘Amr that who related that the Prophet (peace be upon him) said, “Convey (what you know) from me, even if it is a single Ayah (i.e., Qur’anic verse, any prophetic narration).1

It is also related by Ahmad, Al-Tirmidhi, and Ibn Hibban, on the authority of Ibn Mas‘ud (may Allah be pleased with him) that the Prophet (peace be upon him) said, “May Allah give splendor and bliss to a person who hears something from us (i.e. The Prophet) and conveys it exactly as they have heard it, for perhaps the recipient may be more perceptive than the one who heard it.2 This Hadith is also narrated through other Sanads (chain of narrators) in different wordings.

Allah (Exalted be He) gives warning to those who conceal the knowledge, saying: “Verily, those who conceal the clear proofs, evidence and the guidance, which We have sent down, after We have made it clear for the people in the Book, they are the ones cursed by Allâh and cursed by the cursers. Except those who repent and do righteous deeds, and openly declare (the truth which they concealed). These, I will accept their repentance. And I am the One Who accepts repentance, the Most Merciful.” [Al-Baqarah: 159-160]

It is also declared to be Haram (prohibited) to say or discuss things about which people have no knowledge, because of Allah’s saying: “Say (O Muhammad صلى الله عليه وسلم): “(But) the things that my Lord has indeed forbidden are Al-Fawâhish (great evil sins and every kind of unlawful sexual intercourse) whether committed openly or secretly, sins (of all kinds), unrighteous oppression, joining partners (in worship) with Allâh for which He has given no authority, and saying things about Allâh of which you have no knowledge.”” [Al-A’raf: 33] and His Saying: “And follow not (O man i.e., say not, or do not or witness not) that of which you have no knowledge.” [Al-Isra’: 36]

There are also other Nas (Islamic text from the Qur’an or the Sunnah) bearing the same meaning, which encourage the conveyance of the Message of Islam and caution against speaking without knowledge.

Secondly: There are many branches of Islamic knowledge: Tawhid (belief in the Oneness of Allah/monotheism), which has three categories: Tawhid-ul-Rububiyyah (Oneness of Allah’s Lordship), Tawhid-ul-Uluhiyyah (Oneness of Worship), and Tawhid-ul-Asma’ wal-Sifat (Oneness of Allah’s Names and Attributes); Fiqh (Islamic jurisprudence), with its categories of: The Fiqh of ‘Ibadah (worship), which includes Salah (Prayer), Sawm (Fast), Zakah (obligatory charity), and Hajj; the Fiqh of Mu‘amalat (transactions), which includes selling, buying, and leasing; the Fiqh of personal status, which includes marriage, Waqf (endowments), and inheritance; criminal law and the Hudud (ordained punishments for violating Allah’s Law); and the science of Islamic manners and morals. Many books have been written on all of these subjects that are known to the students of knowledge, some of which will be mentioned later.

Thirdly: The introduction to studying the Islamic sciences should begin with the Book of Allah (Exalted be He), and its meanings should be contemplated along with a careful study of the Messenger of Allah’s Sunnah. This should be studied to distinguish the Sahih (authentic) Hadith from the Da‘if (weak), to understand the meanings, and derive the rulings from them. The books of Fiqh that were compiled by the righteous scholars who had studied the Qur’an and the Sunnah and derived rulings from them should also be studied. Some of these are abridged, others complete, and some are easy and others difficult; so they should be read according to the readers’ mental ability, their power of assimilating knowledge, and their needs in their life.

A beginner should start with the easy and the abridged books, such as: The Tafsir (exegesis of the meanings of the Qur’an) of ‘Abdul-Rahman Al-Sa’adi; the Tafsir of Ibn Kathir; and “Subul Al-Salam” by Al-San‘ani, who explained “Bulugh Al-Maram li-Ahadith Al-Ahkam” by Ibn Hajar Al-‘Asqalani. Other important books include: “‘Umdat-ul-Fiqh” by Ibn Qudamah, and “Al-Kafi” by him also, these both deal with Fiqh; “Al-Adab Al-Shar‘iyyah” by Ibn Muflih; “Al-‘Aqidah Al-Wasitiyyah” by Ibn Taymiyyah; and “Kitab Al-Tawhid” and “Kashf Al-Shubuhat” by Shaykh Muhammad ibn Abdul-Wahhab.

As for those who are well-versed and educated, they can choose for themselves the books that will benefit them and consult trustworthy scholars. Some of these books are “Tafsir Ibn Jarir Al-Tabari”; “Fath Al-Bari” by Ibn Hajr, which is a commentary on “Sahih Al-Bukhari”; the commentary of Al-Nawawi on “Sahih Muslim”; “Al-Umm” by Al-Shafi’i; “Al-Mughni” by Ibn Qudamah, “Bidayat Al-Mujtahid” by Ibn Rushd; and other similar books. Those who wish to study any branch of academic, theoretical, or experimental knowledge must have a teacher. This is a globally acknowledged phenomenon among mankind, both Muslims and non-Muslims, for they must cooperate to meet their needs, because of their different abilities, level of acquired knowledge, and the availability of means to assist in the understanding of the different rulings. Students can rely on themselves in the knowledge they find easy to acquire from its authentic sources, as to what they find difficult, they can cooperate with their fellow students to help them understand it or ask trusted scholars.

Fourthly: A Da‘i (caller to Islam) should start to guide people to the Truth by teaching them Tawhid, then the foundations of ‘Ibadah, and what they need to know about Mu‘amalat. This should be done with wisdom, fair preaching, and persuasive discussions, aimed at attaining the Truth, as Allah (Exalted be He) says: “Invite (mankind, O Muhammad صلى الله عليه و سلم) to the Way of your Lord (i.e. Islâm) with wisdom (i.e. with the Divine Revelation and the Qur’ân) and fair preaching, and argue with them in a way that is better. Truly, your Lord knows best who has gone astray from His Path, and He is the Best Aware of those who are guided.” [Al-nahl: 125]

  1. Related by Ahmad, vol. 2, pp. 159, 202, and 214; Al-Bukhari, vol. 4, p. 145; Al-Tirmidhi, vol. 5, p. 40, no. 2669; Al-Darimi, vol. 1, p. 136; ‘Abdul-Razzaq, vol. 6, p. 109 and vol. 10, p. 312, nos. 10157 and 19210; Ibn Hibban, vol. 14, p. 149, no. 6256; Al-Tabarani, Al-Saghir, vol. 1, p. 166; Al-Tahawi, Sharh Ma’ani Al-Athar, vol. 4, p. 128; Al-Quda’i, Musnad Al-Shihab, vol. 1, p. 387, no. 662; Al-Asbahani, Hilyat Al-Awliya, vol. 6, p. 78; Al-Bayhaqi, Al-Adab, p. 454, no. 1217; and Al-Baghawi, vol. 1, p. 243, no. 113. 

  2. Al-Darimi, Sunan, Introduction, no. 230. 

May Allah grant us success. May peace and blessings be upon our Prophet, his family and Companions