Is the following report authentic?
Abdullah bin Qurt narrates :
I then departed from the Masjid via Ethiopia Gate and said to myself, "I will commit a grave error if I fail to make salam at the tomb of Rasulullah, for I do not know whether or not I will see it again."
So I went to the room where 'Aishah was sitting at the grave. 'Ali and al-'Abbas were also present with al-Husayn sitting in 'Ali's lap and al-Hasan in al-'Abbas's lap. They were reciting Suratul-An'am while 'Ali was reciting Surah Hud. I made salam to Rasulullah.
'Ali: O Ibn Qurt, are you going to Syria?
Ibn Qurt: Yes, O cousin of Rasulullah. I think that once I reach there the two armies will already be deeply embroiled in fighting. They will see me coming without help or reinforcements. I really fear that they will become weak and frightened. I wish that I could reach them before they fight so that I can at least advise them and counsel them with patience.
'Ali: So what is stopping you from asking 'Umar to make du'a for you?.
Ibn Qurt: I am well aware of all these virtues of 'Umar which you have mentioned, but in addition I would like your du'a and the du'a of al-'Abbas, the paternal uncle of Rasulullah, especially here at the noble tomb of Rasulullah.
Al-'Abbas raised his hand in supplication. 'Ali, al-Hasan, al-Husayn, 'Aishah (and Hafsah and Umm Salamah who had also arrived) joined them. He prayed, "O Allah, we seek intercession through this chosen Prophet and selected Messenger through whom Adam also sought intercerssion and then You forgave his error. O Allah, make the road easy for 'Abdullah and fold up the long distances for him. Help the Sahabah of Your Prophet with victory. You are the Hearer of Du'a."
He then said, "Go Abdullah, for it is unlikely that Allah will reject the du'a of 'Umar, 'Abbas, 'Ali, al-Hasan, and the wives of Rasulullah, especially when they have interceded through the best of all creation." (Al-Imam al-Waqidi, The Islamic Conquest of Syria, A Translation of Futuhusham: The Inspiring History of the Sahabah's Conquest of Syria, translated by Mawlana Sulayman al-Kindi [Ta-Ha Publishers Ltd., London 2005], Part 3: Al-Yarmuk, pp. 287-288; capital and bold emphasis mine)
When responding can someone also share the Arabic of the du'a from the source given?