`Ubayd Allah was full of eagerness for the war. He was indignant with Mu'awiya, for the latter was the reason for the killing of his two sons in the Yemen. So from the day when `Ubayd Allah withdrew his army from Dir `Abd al-Rahman, he went on hearing the news of Kufa. He knew that there were Shi'ite propagators who went on their lovable way and increasing activity. He hoped that the Shi'ite propagators would help him through their mobilization.
`Ubayd Allah arrived at Maskan, the place where the two fighting armies met. He heard of the summons of the active skillful Shi'ite propagators in Kufa. He knew that the summons mobilized some groups of fighters from the outskirts of Kufa and al-Mada'in. Apart from this, he knew that they went to their camps there.
Also `Ubayd Allah knew that the enemy maneuvers, which some Kufan leaders headed, aborted many efforts of the Shi'ite great figures and hindered the general mobilization.
No wonder! These pieces of news made `Ubayd Allah b. `Abbas angry. They filled his heart with wrath. Thus he was indignant with the people.
`Ubayd Allah's fighters weakened his hope. For they refrained from sending urgent aids for him. Thus he had to make use of these lessons that the conditions of Kufa imposed on him, and to resort to his forces to face the enemy forces. For the enemy forces were ready to fight against him face to face. He heard that they were at least sixty thousand Syrian fighters who were known for their blind obedience for their rulers and commanders.
`Ubayd Allah was indifferent to the large number of the enemy forces. However, he was very careful of the spiritual qualities of the two parties (i.e., Mu'awiya's and `Ubayd Allah's soldiers). Also he attached great importance to the morale of his army. For he had only this army to meet his enemy.
To make a balance between his army and the hostile enemy, `Ubayd Allah thought about the mixed bands in his army. Also he thought about his war that was in need of many loyal strong fighters. So he was very careful of those mixed bands. For they understood nothing of jihad (holy war) except that it was means for booty.
`Ubayd Allah headed for his camp at Maskan. He became very pessimistic. Thus his pessimism had an effect on the steps that followed.
`Ubayd Allah feared for the spirits of his army. For the news of the unsuccessful mobilization spread among the Kufans. Besides Mu'awiya's tricks prevailed them, for they were mere mixed groups at Maskan. This means that he had no confidence in his forces, for they included some persons. They spied for Mu'awiya to corrupt his plan. Cold war was the best of Mu'awiya's weapons. It was not only in this field but also in all fields.
`Ubayd Allah's idea was right.
Suddenly, Mu'awiya's first plot found its way to the Camp of Maskan. At that camp, there were mixed bands: some of them were loyal persons; some of them were hypocrites; some of them were those who preferred rest (to jihad) and hoped that the new rumor would be true. The new rumor was that: "Indeed, al-Hasan is corresponding with Mu'awiya to make peace (with him), so why do you kill yourselves?" 
It was not important for `Ubayd Allah and his loyal companions to hear that false rumor, for they knew that al-Hasan was getting ready to wage war against Mu'awiya through sending messengers to the outskirts of Kufa, and through his orations in Kufa. In other words, they knew that al-Hasan wrote letters to Mu'awiya to wage war against him, not to make peace with him or to give up his idea.
However, it was the excellent trick of the Satan (i.e., Mu'awiya).
The loyal ones from the Ansar (the Supporters) summoned the people to be calm. They asked them for a time till the postman of al Mada'in arrived. Still their words were merely an echo in a valley or a blow in ash. In this way a sorrowful disorder prevailed the fighters of al-Hasan, peace be on him.
Then `Ubayd Allah became weak towards the wicked trick that made a gap in the critical situation.
So he was alone with himself at his tent that was far away from the noise of the people. He thought that this leadership of his would endanger his military position very much, so he got excited for his reputation. Moreover, he was indignant with the words of the people concerning him. Then he repented of accepting it (i.e., the leadership). Among the attacks of the anger in his nature was that he cursed the conditions that opposed him during this military movement of his. Also he cursed the conditions that made him leader in that front. Then he introverted because of a state of worry and of self- love. He did not know what to do.
At last `Ubayd Allah thought that he had to render his resignation (that was the escape which his utmost skillfulness reached). He yielded to his selfish talents on which he depended willingly and intentionally.
After `Ubayd Allah had decided to render his resignation, he had to abandon the headquarters, just as the Imam (i.e., al-Hasan) thought, or to hand it over to his successor Qays b. Sa'd b. `Abbada al-Ansari.
`Ubayd Allah was still at his splendid large tent. The tent was far away from the large tents. It was the only thing that witnessed the mutiny of the betraying leader and heard his indignant mumble and his ungratefulness for the favors he received from his cousins for two generations. Before he left his tent, he had realized that the conditions of the resignation from a certain job would not be complete in the Islamic law but through confessing feebleness openly. However, this man was not ready to subject his character to the scorn of the people. So he came back to himself again to find the escape that would not force him to such a confession.
Also Mu'awiya's letters urged `Ubayd Allah to think about those great temptations whenever he thought to find a solution. It is worth mentioning that he forgot that he had received these letters from the postman who spread the black rumor at his camp in the morning. When he recalled Mu'awiya's letters, he remembered the beautiful dream coated with gold. Still the bitter fact annoyed him. So such a dream paralyzed his thinking and feeling. It prevented him from concluding the idea that was appropriate for him as a Hashimite leader. For he was supposed to fight against the strongest enemy of the Hashimites to win either victory or martyrdom.
`Ubayd Allah was able to render his resignation and to confess feebleness without hesitation and confusion. Through this way he would be able to conclude an excuse for his reputation and dignity. That is because the second leader (i.e., Qays b. Sa'd) was unable to assume the leadership in that critical condition.
Besides `Ubayd Allah was able to endure his attitude, to threaten the rioters, and to take artificial steps to show both violence and guidance. He was able to maintain his religion and reputation through these administrative measures, which he had to master as the other leaders mastered, through patience, and through waiting for the final teachings from the Imam (i.e., al-Hasan).
`Ubayd Allah, who was a commander at the Camp of the Imam, abandoned his glory when he bargained with Mu'awiya's messengers for the wage of the defeat. Thus this deed of his was neither glory nor dignity!
Mu'awiya's letter to `Ubayd Allah stroke the right note of the latter who loved greatness and priority. In his letter to `Ubayd Allah, Mu'awiya said: "Indeed, al-Hasan will be forced  to make peace (with me), so it is better for you to be followed than to be follower."  He (Mu`awiya) limited a thousand dirhams for `Ubayd Allah in the letter. 
Mu'awiya was the most desirous person in making use of the critical situations of his enemies.
Mu'awiya had limitless belief in human lowliness. He thought that the most righteous of people in ethics, the strongest of them in determination, and the purest of them in virtue maybe tempted by greed and subjected by desires at an hour of weakness that overtook their selves, and at a time of doubt that controlled the people. He thought that the best people and the superior human beings were not safe from the calamities of doubt." 
The following are some words with which the Commander of the faithful warned Ziyad against Mu'awiya. He said to him: "Indeed, Mu'awiya exploits man through his two hands, through his back, through his right (hand), and through his left. So beware (of him), then beware (of him)." 
In this way disappointment and greediness overcame the Hashimite young man (i.e., `Ubayd Allah). Suddenly, he became among the most exposed traitors.
So neither the religion, nor lineage, nor tribalism, nor the close relation to the Apostle of Allah, may Allah bless him and his family, and to his high commander (i.e., al-Hasan), nor the covenant with Allah on the day when he was the first to summon the people to pledge allegiance to al-Hasan at the mosque of Kufa, nor the fear of the words of the people, nor the wrath of history were able to prevent `Ubayd Allah from coming to that ignoble end.
`Ubayd Allah sought protection with Mu'awiya at night. He followed the manner of the defeated, deserted person who himself knew the great sin he committed.
Then history has turned away from `Ubayd Allah and has not mention him but in the black list. That was the reward of the traitors. For they dug their graves with their hands, and died intentionally before they were forced to die.
The defeat of `Ubayd Allah b. `Abbas at (the camp of) Maskan created an atmosphere of quick pessimism. The effects of this pessimism were not only on Maskan but also on al-Mada'in. So his defeat was a painful disaster in the full sense of the word.
`Ubayd Allah was responsible for the gradual situations that followed his desertion. Thus he is condemned before Allah and history.
After the desertion of the first leader (i.e., `Ubayd Allah), Qays b. Sa'd b. `Abbada assumed the leadership of the vanguard. Worth mentioning, Qays was the legal commander after `Ubayd. Moreover, he had excellent qualities. For example, he had a pure faith. He was known for his cleverness in the history of the Arabs. He had a remarkable character because he was among the rest of the Companions  of 'Ali, peace be on him. He grew up a holy fighter (mujahid). He was righteous throughout his life. He hated weak fighters. Thus he was indignant with them when they inclined to desires and refrained from carrying out the religious obligations. When he assumed the leadership of the Camp at Maskan, he rose among the rest of the soldiers and addressed them. In his speech he condemned his defeated predecessor (i.e., `Ubayd Allah). He censured him for his shameful attitude. Then he began to refresh the morale of his army, which this violent shock weakened.
He (Qays) said: "Men, what this straying man has done should not terrify you. Don't regard it as great. Indeed, this (man), his father, and his brother never did good some day. Indeed, his father, who was the paternal uncle of the Apostle of Allah, went out to fight against him (Allah's Apostle) (at the Battle of) Badr. So Abu al-Yusir Ka'b b. `Amr al-Ansari captured him. He brought him before the Apostle of Allah. So the latter took his ransom and divided it among the Muslims. (Imam) 'Ali appointed his (i.e., `Ubayd Allah's) brother as governor over Basrah. So he (`Ubayd Allah's brother) stole his (`Ali's) and the Muslim's money. He bought female slaves for it, and claimed that it was his own legal money. Imam ('Ali) appointed this (i.e., `Ubayd Allah) over the Yemen, but he escaped from Bisr b. Artat. He left his two sons to be killed there. Now, he did what he has done. 
Qays was an excellent orator. Thus he made an effective speech to move the feelings of the people against `Ubayd Allah b. 'Abbas. So the people shouted: "Praise be to Allah who brought him (i.e., `Ubayd Allah) out of us." 
I (the author) say: In this way, experiences are keys to know men, as the Arabic proverb says.
 Sharh Nahj al-Balagha, vol. 4, 15.
 I (i.e., the author) say: This text is clear in refuting the rumor that prevailed the Camp of Maskan, that said: "Indeed, al-Hasan exchanged letters with Mu'awiya to make peace with him."
 Al-`Alam al-`Arabi (Magazine, year 11, no. 2, p. 30)
 Ibn al-Athir, al-Kamil fi al-Ta'rikh, vol. 5, p. 176.
 Al-Mas'udi said: "Qays b. Sa'd was great in religious devotion, religion, and inclination to 'Ali. He was very afraid of Allah and very obedient to Him. One day he was praying. When he fell down in adoration, suddenly, there was a great spotted serpent. He moved his head from the serpent and bowed down beside it. However, the serpent encircled his neck. Still he did not shorten his prayers, nor did he decrease anything of them till he finished (them). Then he took the serpent and threw it away. He (i.e., al-Mas'udi) said: "Al-Hasan b. 'Ali b. `Abd Allah b. al-Mughira b. al-Mu'ammar b. Khallad reported a similar narration on the authority of Abu al-Hasan, 'Ali b. Musa al-Rida." Qays died in the year 85 A.H.
 Abu al-Faraj al-Isfahani, Maqatil al-Talibiyyin, p. 35.