At the head of the Persian army Rustam marched against Qadisiyya and encamped on the east bank of the Ateeq. The Muslim forces lay entrenched at Qadisiyya on the west bank of the Ateeq.
Rustam the Commander-in-Chief of the Persian forces sent a message to the Muslim Commander Saad asking him to send on emissary for talks. Saad deputed Rabi bin Amir as the envoy. Rabi crossed the bridge and made for the camp of Rustam. Rabi appeared before Rustam wearing a coat of shining mail over which was wrapped a coarse woollen cloak. Around his head was a veil held by thongs of a camel's girth. His sword hung at his side in a sheath of coarse cloth. In his right hand he carried his spear. Rabi mounted on a shaggy horse arrived at the edge of the carpet at which Rustam and his couriers were seated.
The Persians wanted Rabi to lay aside his arms. Rabi said, "I have not come to you to lay down my weapons. You invited me, and I have come, if you do not wish me to come the way I like, I shall return."
Rustam asked his men to let the Muslim come in the way he wished.
Rustam asked Rabi as to what was their mission. Rabi said that their mission was to spread Islam. He said, "If you accept Islam we are brothers and there is peace between us; if you refuse we fight you and leave things to God."
"What do you expect in return", asked Rustam.
Rabi said, "Victory if we survive, and Paradise if we die fighting in the way of Allah".
Rustam said that he should be allowed some time to think over the matter further.
Rabi said that according to a tradition of the Holy Prophet he could give him a time of three days.
"Are you their chief", asked Rustam.
Ribi said, "No, but the Muslims are like one body, and the lowest is equal to the highest."
The next day Rustam asked again for an emissary. This time Saad deputed Hudhaifa bin Mihsan. He rode over the carpet to Rustam's throne, and remained seated on his horse throughout the talks.
Rustam wanted to know why the envoy of the previous day had not come. Hudhaifa said, 'Our Commander treats us equally in on joying favours and bearing hardships. This time it is my turn."
"What do you expect of us", asked Rustam.
Hudhaifa said, "We would expect you to become Muslims or pay Jizya."
Rustam said, "What if we do not agree to both these alternatives."
Hudhaifa said that in that case the arbitration would rest with the sword. Saying that Hudhaifa rode back from the Persian camp.
For the third time Rustam asked for another envoy. This time Muheera bin Zurara was chosen as the Muslim emissary. Mugheera rode forward and sat on the throne beside Rustam. The Persians wanted to unseat him, but he held fast, and Rustam said, "Let him remain seated."
Looking at the short light arrows which protruded from the quiver of Mugheera, Rustam said, "O Arab what do you do with these spindles?"
Mugheera said, "We shoot them."
"And why is your sword wrapped in rags", asked Rustam.
Mugheera said, "It is clothed in rags but it strikes like steel".
Rustam said that it was perhaps their hardship that had I brought the Arabs to Iraq. He said:
"It shall give your commander a set of clothes, a mule and 1,000 dirhams, and to every man among you two garments and a bag of dates. And you shall go away from us for I have no desire to kill you or take you in captivity."
Mugheera said that times had changed, and because of Islam the Arabs were no longer fighting because they were poor or were subject to any hardship. They were fighting in the way of Allah, and they did not stand in need of any gifts from the Persians.
Rustam thereupon said, "This means that there can be no peace between us. When we go to the battle, we will slay the whole lot of you."
Thereupon Mugheera walked away from the Persian camp.
The following day a delegation consisting of four Muslims namely Busr b. Abi Ruhm; Arfaja b. Harsama, Qirfa b.Zahir and Mazur b. Adi went to see Rustam.
This time Rustam talked in parables. He said:
"We are like the man who had a vineyard and saw a fox in it one day. He said one fox did not matter. But the fox called other foxes to the vineyard. When they had all gathered in it, the owner closed the hole in the wall of the vineyard through which they had entered, and then killed all the foxes.
And you are like the rat who found a jar of grain with a hole in it and went through the hole. His friends called to him to come out but he refused and went on eating the grain until he became fat. Then he felt a desire to show his friends how beautiful he looked, but found that because of his bulk he could no longer get through the hole. So he complained to his friends of his trouble and asked for their assistance. They asked him to starve himself so that he might become as thin as before. The rat starved itself but in the meantime the owner of the jar came to know of it and killed it."
Rustam further said:
"And you are like the fly that saw a bowl of honey and said to his friends, 'Whoever gets me to that honey shall have two dirhams'. The other flies tried to stop him, but he went on to the honey and then into it. As he began to drown in the honey he cried out 'whoever gets me out of the honey shall have 4 dirhams."
Rustam narrated another parable. He said:
"You are like the fox who came into a vineyard, thin and starving and began eating as God wished. The owner of the vineyard saw him and pitying his condition, let him stay. But when the fox had been there for some time and grown big and fat, he turned wicked and started to destroy more grapes than he consumed. This angered the owner, who along with his servants, took a big stick and came after him. The fox dodged them and ran to the hole in the vineyard wall through which he had come, but that hole was big enough for him only when he was thin, and now he was too fat to get through it. So the owner and his servants caught up with him and beat him with sticks until he was dead.
O Arabs you came when you were thin, and now you are fat. See how you get out."
The Arabs said that these parables were idle narrations which carried nowhere. They reiterated their usual demands, Islam, Jizya or sword.
Exasperated Rustam said, "If that is that, let the sword decide."
He asked,"Will you cross the river to our side, or shall we cross to your side."
The Muslims said, "You cross to our side."
When the Muslim envoys returned they apprised Saad of the proceedings. Thereupon the Muslim Commander-in-Chief sent word in the Muslim camp that they should get ready for war.