What is the rationale for calling the rulings of the Shari'ah "obligations" when they include recommended acts?

Question : The question asks: How do we call the rulings of the Shari'ah "obligations" when some of them, such as voluntary acts, do not impose an obligation?

Answer : The answer to this is that we say they are "obligations" in the sense that the servant is commanded to do them or prohibited from doing them. Even the recommended act is an obligation in that one is required to believe that it is prescribed as a recommendation. The disliked act is an obligation in that one is required to believe that it is prohibited by way of disliking it, specifically disliking of deprecation (tanzihi). It is not the case that "obligations" mean that a person is required to do what he cannot do; that is impossible, because He said: Thus, He negated and affirmed: He negated the obligation of what is beyond one's capacity and negated the obligation of what is not within one's capacity.