A bisa wasiyyar Abubakar Umar zai ci gaba da mamaye Sham da Mesofotamiya .A kan iyakar arewa maso gabas na Daular, a Mesofotamiya, lamarin yana kara tabarbarewa cikin sauri.A zamanin Abubakar Khalid bn al-Walid ya bar Mesofotamiya tare da rabin sojojinsa na sojoji 9000 don ya zama kwamanda a kasar Sham, daga nan ne Farisawa suka yanke shawarar mayar da yankinsu da suka bata.An tilastawa sojojin musulmi barin yankunan da aka mamaye, suka maida hankali kan iyaka.Nan take Umar ya aika da dakarun da za su taimaka wa Muthanna bn Haritha a Mesopotamiya a karkashin jagorancin Abu Ubaid al-Thaqafi.A wancan lokacin an yi ta gwabza fada tsakanin Farisawa da Larabawa a yankin Sawad kamar Namaraq da Kaskar da Baqusiatha, inda Larabawa suka ci gaba da kasancewa a yankin.Daga baya Farisawa sun ci Abu Ubaid a yakin gada.A al'adance ana yin ta ne zuwa shekara ta 634, kuma ita ce babbar nasara ɗaya tilo ta Sassania akan sojojin musulmi masu mamaye.