"Sakina" is the Spirit of Tranquility, or Peace of Reassurance. It is a derivative of the original word "Sakina" which is mentioned in the Qur'an as having descended upon the Islamic Prophet (, "") Muhammad and the believers as they made an unarmed pilgrimage to Mecca, and were faced with an opposing military force of the Quraysh, with whom Muhammad struck the Treaty of Hudaybiyah. "He it is Who sent down the "sakina" into the hearts of the believers that they might add faith unto their faith" (48:4).