Sayyidina Abu Hurayrah (RA) narrated : Allah’s Messenger sent us with an army. He said, “If you find so-and-so-and so-and-so, two men, then burn them in the fire.” As we were about to depart, he said, “I had ordered you to burn so-and-so and so-and-so in the fire, but no one punishes by burning in the fire except Allah. So if you find them, slay them.”
[Bukhari 3016]