When Muhammad died in 632 the matter of his succession took place at the Saqifah of Banu Sa'ida, Abu Ubaidah was there along with Abu Bakr and Umar. Umar said to Abu Ubaidah to stretch forth his hand for the caliphate, but he refused and said to Abu Bakr to stretch forth his hand to take the pledge of alliance. After the Ridda wars when Abu Bakr sent Khalid ibn al-Walid to Iraq to conquer it, he sent four Muslim armies into the Levant, making Abu Ubaidah commander of one of them. His target was selected to be Emessa and he was ordered to move through the Tabuk region after the army of Sharjeel ibn Hassana.