What did Muhammad say that every Muslim should to do in his lifetime, if he is able? complete the hajj, a pilgrimage to Mecca
memorize the Quran, or Koran
join a jihad, or holy war
meet a caliph in person

Believing that God had chosen him as his messenger Muhammad began to preach what God had revealed to him. The simple and clear-cut message of Islam, that there is no God but Allah, and that life should be lived in complete submission to the will of Allah, was attractive to many people, and they flocked to hear it.

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All able Muslims must make a pilgrimage (hajj) to Mecca at least once in their lifetimes.

the hebrew bible is the sacred text of judaism;

the koran is that of islam.

among eastern religions, the sacred scriptures of hinduis are the four vedas and the upanishads, among others.

a main characteristic in these books is that un most of them we find certain "norms" of behavior, as is the case of the bible that has it's commandments. these rules are to regulate the behavior of believers and faithful of their respective faith.

these rules tell us what is right and what is not.