Mishkat al-Masabih
Jihad — Hadith #3798
وَعَنْ سَلَمَةَ بْنِ الْأَكْوَعِ قَالَ أَتَى النَّبِيُّ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ عَيْنٌ مِنَ الْمُشْرِكِينَ وَهُوَ فِي سَفَرٍ فَجَلَسَ عِنْدَ أَصْحَابِهِ يَتَحَدَّثُ ثُمَّ انْفَتَلَ فَقَالَ النَّبِيُّ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ: «اطْلُبُوهُ وَاقْتُلُوهُ» . فَقَتَلْتُهُ فنفَّلَني سلبَه
A spy of the polytheists who came to the Prophet when he was on a journey sat and talked with his companions and afterwards withdrew. The Prophet then said, “Look for him and kill him,” so I killed him and the Prophet gave me the spoil taken from him.
(Bukhari and Muslim.)