The migration of the Muslims to Yathrib caused a great stir in the Quraish camp. They felt that if the Muslims gained strength in Yathrib, they would be a source of great danger for the Quraish. The Quraish held a council of war under the leadership of Abu Sufyan and Abu Jahl. The Quraish felt that as long as Muhammad lived, be it in Makkah or elsewhere, he would continue to be a great challenge for the Quraish. The Quraish took cognizance of the fact that in spite of their hostility, Islam was fast spreading in various parts of Arabia. They viewed the process of the growth of Islam with great concern and alarm. They held that in the circumstances their safety lay in the assassination of Muhammad (peace be on him). The Quraish resolved that Muhammad (peace be on him) should be assassinated before he could proceed to Yathrib. The Council of war decided that the young men belonging to all sections should surround the house of Muhammad at night, and assassinate him when he came out of his house in the morning by falling on him in a body, and putting an end to him with the blows of their daggers.
"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