In late 638, following Khalid's invasion of Byzantine Armenia in eastern Anatolia, Khalid was dismissed from army by Umar. The exact reason remained unknown, but various scholars including Muslims and non-Muslims argue that Khalid's dismissal from army at zenith of his power was due to the fact that Muslims started having faith in Khalid's command rather than God for being victorious which worried Umar, who saw this as a threat to religious believes of Muslims which says only to rely on God. Also, a poet wrote some poetry on Khalid's bravery and Khalid being impressed, gave him some award.