-->
The Banu Nadeer were a Jewish tribe who had their settlement outside Madina. The Holy Prophet had given them a charter of freedom and they were expected to be loyal to the Muslims. They however indulged in activities prejudicial to the interests of the Muslims. Kaab b Ashraf a notorious poet of the tribe composed lampoons satiring Islam and the Holy Prophet. He visited Makkah and wrote elegies commemorating the death of the Quraish who had fallen in the Battle of Badr. Kaab was killed by a Muslim young man and the Jews felt bitter at his death. Another Jew of Banu Nadeer, Abu Raafi' Sallarn incited the Arab tribes of Sulaim and Ghatfan to rise against the Muslims.
"When a person dies, his works end, except for three: ongoing charity, knowledge that is benefited from, and a righteous child who prays for him."
Prophet Mohammed (PBUH)
"The best of what a man leaves behind are three: a righteous child who supplicates for him, ongoing charity the reward of which reaches him, and knowledge that is acted upon after him."
Sunan Ibn Mājah
"Every day two angels come down from Heaven and one of them says, 'O Allah! Compensate every person who spends in Your Cause,' and the other (angel) says, 'O Allah! Destroy every miser.'"
Sahih Bukhari