On the occasion of the battle of Uhud, the Jews of Banu Nadeer resorted to treachery. They entered into secret negotiations with the Quraish and even planned to assassinate the Holy Prophet. After the battle of Uhud, these Jews were asked to explain their conduct and when they could offer no satisfactory explanation they were served with an ultimatum of war. They accepted the ultimatum and shut themselves in their strongholds. After a few days they surrendered. They were required to leave Madina. They were allowed to take away whatever movable property they could except arms.
"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