"The Messenger of Allah ﷺ sent us with an army and said: 'If you see so-and-so, and so-and-so' referring to two men from the Quraish: 'then burn them with fire.' Then, upon our departure, the Messenger of Allah ﷺ said: 'I ordered you to burn so-and-so, and so-and-so with fire, and indeed, none punishes with fire except Allah. So if you see them, then kill them.'" There are narrations on this topic from Ibn 'Abbas and Hamzah bin 'Amr Al-Aslami.  

بَعَثَنَا رَسُولُ اللَّهِ ﷺ فِي بَعْثٍ فَقَالَ إِنْ وَجَدْتُمْ فُلاَنًا وَفُلاَنًا لِرَجُلَيْنِ مِنْ قُرَيْشٍ فَأَحْرِقُوهُمَا بِالنَّارِ ثُمَّ قَالَ رَسُولُ اللَّهِ ﷺ حِينَ أَرَدْنَا الْخُرُوجَ إِنِّي كُنْتُ أَمَرْتُكُمْ أَنْ تَحْرِقُوا فُلاَنًا وَفُلاَنًا بِالنَّارِ وَإِنَّ النَّارَ لاَ يُعَذِّبُ بِهَا إِلاَّ اللَّهُ فَإِنْ وَجَدْتُمُوهُمَا فَاقْتُلُوهُمَا قَالَ وَفِي الْبَابِ عَنِ ابْنِ عَبَّاسٍ وَحَمْزَةَ بْنِ عَمْرٍو الأَسْلَمِيِّ