Khums is obligatory. In brief, it means paying one-fifth of the surplus of one’s income after taking away the expenses of the person and his dependents. It consists of two equal parts: one being the share of the Imam (Sehm-e-Imam), meaning that this part goes for constructing masjids, Islamic seminaries, Islamic schools, libraries, hospitals or clinics, orphanages, printing of the Noble Quran, hadith books, Islamic books and lectures, and others things which will benefit, defend, or propagate Islam. The second part is the portion for the poor syeds — descendants of the Prophet — (Sadaat), since they are banned from receiving zakat (charity).