The reward for teaching worldly sciences if one intends thereby to benefit the Muslims

Question : Honorable Shaykh, does teaching people mathematics, sciences, and the like earn a person a reward if he intends by it to call people to Allah the Exalted?

Answer : If these mathematics are of benefit to Muslims in their worldly affairs or their hereafter, and one intends by them to benefit Muslims, then he will be rewarded for his intention. However, they are not like the religious sciences; if they are among the permissible things, they serve as a means. If they are a means to what benefits people in their worldly affairs and hereafter, he is rewarded for them. This is because the legal principle is that the permissible—and I think you know how many categories the legal rulings of obligation are divided into? How many? Five categories: obligatory, forbidden, permissible, disliked, and recommended. The category of the permissible is broad; it depends on what it serves as a means to. It may be forbidden, it may be obligatory, it may be disliked, and it may be recommended. Do you allow me to give an example of this? The default ruling for a sale is that it is lawful, is it not? Is it lawful or forbidden? Lawful, by the saying of Allah the Exalted: "And Allah has made lawful sale." But it may sometimes be obligatory, it may be forbidden, it may be recommended, and it may be disliked. If a person wants to buy from you something that will save his life, such as if he needs food and wants to buy food from you, what is the ruling on the sale? Is it obligatory? Good. A person wants to buy grapes from you to make them into intoxicants? The sale is forbidden. I mean that the grapes themselves are lawful. Good. A person wants to buy water to perform ablution with, and he has no water, so the purchase is obligatory. Based on this, we say that if the permissible is a means to a prescribed matter, it becomes prescribed; if it is a means to a forbidden matter, it becomes forbidden. Yes.