سورة At-Taubah ( The Repentance ) - الآية 5

Then when the Sacred Months (the Ist, 7th, 11th, and 12th months of the Islamic calendar) have passed, then kill the Mushrikun (see V. 2:105) wherever you find them, and capture them and besiege them, and prepare for them each and every ambush. But if they repent and perform As-Salat (Iqamat-as-Salat), and give Zakat, then leave their way free. Verily, Allah is Oft-Forgiving, Most Merciful.