There was a mutual defense treaty between Muslims and nearby Jews in Madinah. The Jews betrayed the treaty by planning to kill the Prophet and allying with enemies including the Quraysh tribe and Ghatafan tribe, amassing an army of 10,000 to fight the Muslims. In response, upon the suggestion of Salman Farsi, the Muslims dug a trench to defend Madinah. When the enemy forces arrived and saw the trench, which was an unfamiliar defense tactic, they were shocked. After over 20 days of siege involving arrow fights and challenges between warriors, the failure to overcome the trench defense marked the beginning of Muhammad's growing political strength in Madinah.