Allah's Messenger (ﷺ) sent us in a mission (i.e., an army-unit) and said, "If you find so-and-so and so-and-so, burn both of them with fire." When we intended to depart, Allah's Messenger (ﷺ) said, "I have ordered you to burn so-and-so and so-and-so, and it is none but Allah Who punishes with fire, so, if you find them, kill them (i.e., don't burn them)."