In pursuance of the arbitration agreement executed between Ali and Muawiyah at Siffin the two umpires Abu Musa Ashari, and 'Amr b Al'Aas met at Dumatul Jandal midway between Kufa and Damascus in January 658 C E. Each side sent a retinue of four hundred persons to witness the proceedings. The retinue from Kufa was led by Abdullah bin Abbas and Shuraih b Mani. The empires invited some notable companions from Makkah and Madina who were known for their neutrality in the dispute between Ali and Muawiyah to come to Dumatul Jandal, Those who responded to the invitation included Abdullah b Umar; Abdullah b Zubair; Mughira b Shuba; and Abdur Rahman b Harith. Sa'ad b Abi Waqas was prevailed upon by his son to go to Dumatul Jandal, but he declined to do so, saying that he was not interested in the affair.
"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