Uhud, a few miles from Madina was a great stretch of barren rock rising out of the desert without any growth of vegetation. The Holy Prophet commanded the Muslim warriors to take up their position at Uhud on the rising ground. A band of archers took up position on an adjoining mound behind the main position. The archers were commanded not to abandon their posts under any circumstances, without the approval of the Holy Prophet.
"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