The Muslims met a man with some sheep of his. He said: Peace be upon you. But they killed him and took those few sheep. Thereupon the following Qur'anic verse was revealed: "...And say to anyone who offers you a salutation: Thou art none of believer, coveting the perishable good of this life." meaning these few sheep. (Using translation from Abū Dāʾūd 3974)   

السَّلَامُ عَلَيْكُمْ فَقَتَلُوهُ وَأَخَذُوا غَنِيمَتَهُ فَأَنْزَلَ اللهُ تَعَالَى {وَلَا تَقُولُوا لِمَنْ أَلْقَى إِلَيْكُمُ السَّلَامَ لَسْتَ مُؤْمِنًا تَبْتَغُونَ عَرَضَ الْحَيَاةِ الدُّنْيَا} [النساء 94] تِلْكَ الْغَنِيمَةُ