The Knowledge Obligatory upon the One Who Is Accountable

Question:
We begin this pleasant and blessed meeting with a message from Algeria (S. H), using this name as a code for his identity, al-Balid. He says in this question: Your Eminence! What is the obligatory knowledge? Is it religious? Or worldly? Or both? Please inform us, may you be rewarded, and may Allah reward you with good.

Answer:
In the name of Allah, the Most Gracious, the Most Merciful. Praise be to Allah, and may Allah send blessings and peace upon the Messenger of Allah, and upon his family and his Companions, and upon those who follow his guidance.
As for what follows:
Indeed, knowledge is of two types: religious knowledge and worldly knowledge.
Religious knowledge is obligatory for every accountable person to learn what Allah has made obligatory upon him, what Allah has forbidden, and what he cannot afford to be ignorant of, as the scholars have explicitly stated. It is obligatory for every accountable person, male or female, to learn what Allah has made obligatory upon him, and to understand his religion, knowing what Allah has made obligatory, such as prayer and others, and knowing what Allah has forbidden upon him, such as shirk (associating partners with Allah) and others, so that he worships his Lord with insight. Many of the scholars express this by saying: It is obligatory for the accountable person to learn from his religion what he cannot afford to be ignorant of. The meaning is: to learn what Allah has made obligatory upon him and what He has forbidden upon him. He learns the meaning of "La ilaha illa Allah" and what it means, and what is the meaning of the testimony that Muhammad is the Messenger of Allah. What is prayer? What is zakah (the obligatory alms)? What is fasting in Ramadan? What is Hajj (the major pilgrimage)? He learns these things that Allah has made obligatory upon him.
And he learns the things that Allah has forbidden: What is zina (unlawful sexual intercourse)? What is riba (usury or interest)? What is an intoxicant? He learns so that he knows the obligatory and performs it, and so that he knows the forbidden and avoids it according to his ability. [al-Taghabun:16] He learns according to his ability by asking the scholars, by reading the Qur'an and understanding it, by reading the hadiths of the Prophet (peace and blessings be upon him), by attending circles of knowledge, by asking through correspondence, by telephone. He strives according to his ability. It is obligatory for him to learn according to his ability. [al-Taghabun:16] He does not remain silent or accept ignorance, but he learns; because he was created to worship Allah, as Allah the Exalted said: [al-Dhariyat:56] We are commanded to do so, [al-Baqarah:21]. So this worship for which he was created and which he is commanded to perform, he must know it. What is worship? He must learn so that he knows this worship for which he was created and which Allah has made obligatory upon him, which is: performing the obligations of Allah and leaving the prohibitions of Allah.
And its foundation and basis is the tawhid (the oneness of Allah) of Allah, sincerity to Him, and faith in Him and in His Messenger Muhammad (peace and blessings be upon him), and faith in everything that Allah and His Messenger have informed about, whether it has happened or will happen, regarding the matters of the Hereafter, Paradise and the Fire, the Reckoning and the recompense, and what has passed of Allah's creation of Adam and the sending of the messengers. He believes in everything that Allah and His Messenger have informed about with insight, and knows that this is the truth, and acts by performing what Allah has made obligatory and ceasing from what Allah has forbidden. This is obligatory upon him according to his ability, through circles of knowledge, through reflecting on the Qur'an, through preserving the Sunnah, through asking the scholars, through correspondence... and so on. He does not neglect it or be lax.
As for the second category: the sciences of the world, he learns from them what helps him to earn a livelihood, to satisfy his needs, so that he can fulfill what Allah has made obligatory upon him. How he sells, how he buys, how he works to cause the provision that sustains his state. He does not just sit in his house and do nothing. He must learn something by which he can assist himself in obeying his Lord. Any knowledge... that is permissible and by which he obtains sufficient provision, praise be to Allah. And if he does not know, he asks. He asks the people of insight from his neighbors... from his relatives... from his colleagues, until he learns something that benefits him, whether selling or buying, or hiring himself out, or gathering firewood or mowing grass. In the time of the Prophet (peace and blessings be upon him), they learned, and many of them would go to the wilderness and bring back firewood, bring back grass to sell, and save themselves and those under their care. Some of them would go and carry firewood and the like, and come back to sell and give charity to the poor. When the Prophet (peace and blessings be upon him) commanded charity, many of the Companions would carry things on their backs for the needs of people, and then give the wage as charity. So the Muslim must learn from the world what helps him to satisfy his need and his requirement in clothing, food, shelter, and the like, and learn what helps him to fulfill the needs of his family.
So he has two types of knowledge and two types of action: Knowledge of the Hereafter, which is the most important and the most obligatory, is to learn his religion, understand his religion, act upon what Allah has made obligatory upon him, and cease from what Allah has forbidden upon him. And he also has a second type of knowledge and a second type of action, which is learning what obtains provision and sufficiency, and fulfilling the needs of his family from the matters of the world. And he acts upon it, whether by gathering firewood, mowing grass, selling, buying, hiring himself out... and so on. He learns the means by which sufficient provision is obtained that sustains his state and the state of those under his care. And Allah is the guarantor of success.

The presenter: May Allah reward you for us and for the Muslims with the best reward, Your Eminence! What about learning other sciences, Your Eminence, like physics, chemistry, and others?

The Shaykh: Whatever benefits people and has no harm, he learns it. Mathematics, physics, whatever has benefit for the Muslims, he learns it, and there is no blame in it, if there is no religious harm. So the sciences that are used to assist in matters of religion or the world, and in which there is no evil, there is nothing wrong with them, whether they are from the sciences of the predecessors or from the sciences of the successors. Any knowledge that benefits people and does not contain what angers Allah, does not contain riba (usury or interest), does not contain disobedience, and does not contain deception of people, but are only sciences that benefit and some people need, and do not contain deception of anyone, or injustice to anyone, or stepping into disobedience, there is no blame in them, praise be to Allah.

The presenter: May Allah reward you with good, O Shaykh.