سورة At-Taubah ( The Repentance ) - الآية 5

Then when the [four] sacred months[6] are over, kill the polytheists wherever you find them, seize them, besiege them and lie in wait for them on every route[7]. But if they repent, establish prayers and give zakah, then set them free, for Allah is All-Forgiving, Most Merciful[8].