عَن أبي تَمِيمَة قَالَ: شَهِدْتُ صَفْوَانَ وَأَصْحَابَهُ وَجُنْدَبٌ يُوصِيهِمْ فَقَالُوا: هَلْ سَمِعْتُ مِنْ رَسُولِ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ شَيْئًا؟ قَالَ: سَمِعْتُ رَسُولَ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ يَقُولُ: مَنْ سَمَّعَ إِنَّ أَوَّلَ مَا يُنْتِنُ مِنَ الْإِنْسَانِ بَطْنُهُ فَمن اسْتَطَاعَ أَن لَا يَأْكُل إِلا طيبا فَلْيَفْعَلْ وَمَنِ اسْتَطَاعَ أَنْ لَا يَحُولَ بَيْنَهُ وَبَيْنَ الْجَنَّةِ مِلْءُ كَفٍّ مِنْ دَمٍ أَهَرَاقَهُ فَلْيفْعَل. رَوَاهُ البُخَارِيّ
Abu Tamimah (may Allah have mercy on him) narrates: I was present with Safwan (may Allah have mercy on him) and his companions, and Jundub (may Allah be pleased with him) was advising and admonishing them. They asked: Have you heard anything from the Messenger of Allah (peace and blessings be upon him)? He said: I heard the Messenger of Allah (peace and blessings be upon him) say: "Whoever performs a deed for the sake of fame, Allah will disgrace him on the Day of Resurrection (showing that he acted with this intention), and whoever puts himself into hardship, Allah will put him into hardship on the Day of Resurrection." They said: Advise us. He said: The first thing in a person's body to become corrupt is his stomach, so whoever is able to eat only what is lawful should do so, and whoever is able to ensure that nothing stands between him and Paradise except a handful of blood which he has unlawfully shed, then he must certainly avoid shedding unlawful blood. Narrated by al-Bukhari.