Mishkat al-Masabih 329
Anas b. Malik said:
Ubayy, Abu Talha and I sat and ate some meat and bread, after which I called for water to perform ablution. They asked, “Why are you performing ablution?” and I replied that it was because of this food which we had eaten. They said, “Do you perform ablution after eating things which are good? He who was better than you did not perform ablution on that account.” 

Ahmad transmitted it.
وَعَنْ أَنَسِ بْنِ مَالِكٍ قَالَ: كُنْتُ أَنَا وَأَبِي وَأَبُو طَلْحَةَ جُلُوسًا فَأَكَلْنَا لَحْمًا وَخُبْزًا ثُمَّ دَعَوْتُ بِوَضُوءٍ فَقَالَا لِمَ تَتَوَضَّأُ فَقُلْتُ لِهَذَا الطَّعَامِ الَّذِي أَكَلْنَا فَقَالَا أَتَتَوَضَّأُ مِنَ الطَّيِّبَاتِ لَمْ يَتَوَضَّأْ مِنْهُ مَنْ هُوَ خَيْرٌ مِنْك. رَوَاهُ أَحْمد