32-13 Muhammad ibn Ibrahim ibn Ishaq al-Taliqani - may God be pleased with him - narrated that Ahmad ibn Muhammad ibn Sa’eed al-Kufi al-Hamdani quoted on the authority of Ali ibn Al-Hassan ibn Fadhdhal, on the authority of his father that Abil Hassan Ar-Ridha’ said,

“Why were the Best Messengers called the ‘Ulul-Azm?” The Imam answered, ‘They were called the ‘Ulu-Azm since they had laws and regulations. The Prophets that came after Noah all followed thelaws of Noah , and followed him. The Prophets that came after Noah all followed his Book until Abraham came. The Prophets that came after Abraham all followed Abraham’s laws. The laws and the ways of Abraham were followed by all the Prophets that came after Abraham until Moses . Then after Moses , the Prophets followed his laws and ways and adhered to his Book until the time of Jesus . All the Prophets at the time of Jesus and after him followed his laws and ways and adhered to his Book until the time of our Prophet Muhammad (S). Therefore, these five Prophets are the ‘Ulul-Azm and are the best of the Prophets and Messengers. The laws of Muhammad will not be voided until the Resurrection Day. No Prophet will ever come after him until the Resurrection Day. It is incumbent to kill whoever claims Prophethood after him or brings a book after the Qur’an for anyone who hears his claim.’”