The Wager. Ubaiy b Khalf a Quraish leader said to Abu Bakr, "If you are sure, let us have a wager. That will show where the truth lies." Abu Bakr said "Agreed". The revealed verses did not specify any time limit about the fulfillment of the prophesy. Abu Bakr consulted the Holy Prophet as to the time limit and he said that God willing the prophesy would be fulfilled within nine years. Abu Bakr accordingly entered into a wager agreement with Ubaiy b. Khalf. According to the agreement it was stipulated that the party which lost the wager would pay one hundred camels to the other party. The time limit for the fulfillment of the prophesy was fixed at nine years. It was further laid down that the agreement would be binding on the heirs of the parties.

Fulfillment of the prophesy. Within a few years the Byzantines were strong enough to launch an attack against Persia. In the battle of Issus in 622 C.E. the Persians suffered the first defeat. Other battles were fought during 623-25 in which the Byzantines had the upper hand. The decisive battle was fought on the banks of the Tigris near the city of Mosul in 627 C.E. when Persia surrendered and asked for terms. As a result of this reverse there was a revolt against the Persian king Khosroes II who was killed by his own son Sherwayh. Sherwayh made peace with the Byzantines by abandoning all the conquests that Persia had made earlier. Thus the promise of God as made in Surah Ar-Rum was literally fulfilled. By this time Ubaiy was dead, but his heirs honored the agreement and gave a hundred camels to Abu Bakr!

They also accepted Islam, for the fulfillment of the prophesy was a proof positive of the truth of Islam. Abu Bakr gave away all the hundred camels as Sadaqa.