Hadith 530
وَحَدَّثَنِي عَنْ مَالِكٍ، عَنِ ابْنِ شِهَابٍ، أَنَّهُ قَالَ الْمَشْىُ خَلْفَ الْجَنَازَةِ مِنْ خَطَإِ السُّنَّةِ .
Yahya related to me from Malik that Ibn Shihab said, "Walking behind the bier is in contradiction to the sunna
Maqtu Sahih (Salim al-Hilali)
Muwatta Malik 530 · Book 16, Hadith 11