It is narrated from Sayyiduna Hamzah bin Amr al-Aslami (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) sent a man (saying): "If you find so-and-so and so-and-so, burn them with fire." When he was about to leave, he (peace and blessings be upon him) called him back and said: "None may punish with fire except the Lord of the fire."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب السير / 18064