 According to Rudi Paret, Muhammad's "most dangerous rival" was now on Muhammad's side.In 630, when Muhammad's launching a campaign against the Byzantine Empire during a time of drought and food shortage created serious discontent in Medina, Ibn Ubayy expressed his sympathy for those criticizing the expedition as untimely.As the army assembled, Ibn Ubayy's troops formed a separate camp and turned back to Medina when Muhammad's forces set out.