On the appointed date, Barq b Abdullah attacked Muawiyah at Damascus while he was leading the Fajr prayers. The murderer was caught red handed. His feet and tongue were cut off in the first instance. He was thereafter subjected to other tortures, and ultimately put to death.
The wound that Muawiyah received was not fatal. His physicians offered him two alternative cures, one being cautery, and other was the drinking of a draught which would neutralize the poison, but would render him impotent. Muawiyah adopted the second alternative, and he was duly cured after a few days. The Kharijite plot to murder Muawiyah thus came to naught.
"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