A Muslim has to know the rulings pertaining to the purification of the body, salah, zakah (if he is rich), and fasting. He must also know the rulings related to what is lawful and unlawful regarding kinds of food and drinking, dressing, adornment, and so on. A Muslim can obtain this knowledge through tapes, videos, contemporary books [on the relevant subjects], and the Internet. But he must make sure that the scholars he receives knowledge from are qualified, trustworthy and truly religious. This is to say, scholars are to be knowledgeable about fiqh and Hadith, and must be aware of the objectives of the Shari`ah in general. They are to have wide knowledge about the different schools of the righteous predecessors and those who followed them and are to be flexible with regard to giving fatwas, especially if there is sufficient evidence to support their views.
Sheikh Yusuf Al-Qaradawi, states the following: A Muslim must know the rulings of Islam pertaining to the obligations and teachings he has to adhere to in his life. He must know the rulings related to purification of the body, the prescribed five daily prayers, and Friday prayer. He has to know the basics in these respects; he is not required to go into the details and complex questions which concern scholars more, the same goes for fasting, zakah, and Hajj. A Muslim should learn the rulings he is to abide by to perform these obligations. As for zakah, if a Muslim has sufficient wealth (which is stipulated in the Shari`ah), he is to know the amount of zakah he must pay concerning the kind of wealth he possesses. If he is a merchant, for example, he is to study the zakah on trade, and he is not required in this case to acquire knowledge about zakah on animals or plants. Also, if he can afford to perform Hajj, he is to learn the rulings regarding it.
A Muslim must also know what is lawful and unlawful regarding matters of daily life like eating, drinking, dressing, adornment, household, work, family and community. (I have tackled this in my book The Lawful and the Prohibited in Islam which was printed more than fifty times in Arabic, and translated into
many languages, thanks to Almighty Allah.)
Every Muslim must also learn the rulings relevant to his roles in life: a ruler must know the rulings regarding leadership, a merchant has to learn the rulings pertaining to trade, a doctor must know the rulings related to medicine, spouses and parents have to learn the rulings concerning their duties and rights, and so on.
Concerning ethics, a Muslim must learn the kind of behaviour that he should adhere to. He is not to deviate from the orders that Almighty Allah has ordained, nor is he to commit any prohibition He, the Almighty has forbidden. [In a word], a Muslim is to abide by virtue and shun vice.
A Muslim can obtain knowledge in the above fields by one (or both) of two ways: attending lessons given by trustworthy scholars who are both qualified and broad-minded, or by means of personal reading.
Receiving knowledge at the hands of scholars is the most useful way for illiterate people to acquire knowledge. A Muslim in this case is to be careful when choosing a scholar to receive knowledge from. He is to differentiate also between the scholar who gives admonitions and reminds Muslims of the importance of remembrance of Almighty Allah, and the one who is knowledgeable about the Shari`ah and gives lawful rulings. Not all Muslim preachers have a great influence on Muslims, or are eloquent, nor are all scholars qualified enough to give fatwas. Allah the Almighty has distributed skills and capabilities in the field of acquiring knowledge among people, and there are few who have comprehensive knowledge about all fields of the Shari`ah. Unlettered Muslims, and even many literate ones, are not aware of this fact. They regard any one giving them admonitions [in mosques] as a knowledgeable scholar who they can resort to and enquire about the rulings of the Shari`ah. These Muslim preachers often answer the questions they receive according to their limited knowledge which often causes them to give incorrect answers. If those preachers were fair they would say to the people who direct questions to them concerning Shari`ah: “Ask qualified scholars about this. I cannot give you answers on these matters.” There is an agreed upon hadith that warns against asking people who give answers not based on firm knowledge and thus deviate from the right path and lead people astray too.
another means of acquiring knowledge is through listening to audio cassettes and watching videos about religious matters. This is an important and effective means. One may use an audio cassette in his car or shop, and women may use it while doing household chores. Religious programs broadcasted on television and radio are also beneficial. At the same time, Muslims are to be careful when choosing cassettes and videos. Not all tapes recorded on religious subjects are dependable or worthwhile listening to. Some tapes of this kind, in fact, do more harm than good, for they are not based on authentic sources or reliable evidence from the Shari`ah. Also many of these tapes focus on implanting fear, in an exaggerated way, in people’s hearts about the punishments in the grave and the Hereafter. Thus they make things difficult for people rather than easy, and adopt an approach that intimidates rather than calls people to do good. This goes against the instruction of the Prophet (peace and blessings be upon him) that teaches Muslims to make things easy, not difficult and to give people glad tidings rather than develop feelings of aversion in them.
Once a man told me that his daughter would wake up at night feeling terrified after she had listened to a tape about the punishment that will befall sinful people in the grave.
When seeking knowledge through reading books, Muslims should choose books that were written by knowledgeable scholars.

The Internet is also a good source for obtaining knowledge about Islam. In fact, the written word will remain the most valuable and effective source of obtaining knowledge and culture. Muslims are to be careful when choosing reading material, and especially regarding religious subjects, they should take into account that not all books are trustworthy sources of knowledge. A wise scholar once said: “Tell me what you read, and I (will) tell you who you are.”
There are books that deceive ordinary Muslims, that is, they seem to call for goodness while they are really not calling for piety at all. These include books written by atheists, secularists, Marxists, and the like.
Whatever means the Muslim uses to acquire knowledge about Islam, he is to be careful regarding the authenticity of the source. Not any piece of information about Islam or any person talking about it is a dependable source. Muslims are to bear in mind that there are many books [and Internet sites] that contain distorted information about Islam.
Muslims are also to be aware of the false information cunningly included by hypocrites (especially the Jews) into the exegesis of the Qur’an, the false and weak hadiths reported to have been said by the Prophet (peace and blessings be upon him), and the unreasonable stories or dreams related to admonish or intimidate people into doing something.
Hence, I reemphasize that the Muslims, who seek to obtain true knowledge about Islam, should be careful when choosing the scholars from whom they are to receive knowledge, especially knowledge about Prophetic hadith, for not all scholars are knowledgeable in this subject.
I also advise them to have some authentic books on hadiths such as Al-Maqasid Al-Hasanah by As-Sakhawi, and Kashf Al-Khafa’ wa Muzil Al-‘Ilbas fima Ishtahara min Al-hadith `ala Al-sinat An-Nas by Al-`Agluni.
I believe that there should be censorship on the books [and other means of publication] just as there is censorship on food products to ban contaminated or out-of-date goods. Contaminated thoughts are, in fact, far more dangerous than contaminated food.
I would also like to draw the Muslims’ attention to the fact that early Islamic books [that are considered valuable resources on religious knowledge] are not easy to understand by all people. In order for an ordinary person to obtain knowledge about these books, he should attend the lessons of a knowledgeable scholar. Should an ordinary person read them on his own, he would be like a person wandering in a desert without a guide to show him the way.
That is why knowledgeable scholars warn against receiving knowledge from those who depend on books as their sole source of knowledge without attending scholars’ lessons. Some universities even stipulate that their students attend no less than 70 percent of the lectures in order to pass their courses.