Musnad Ahmad 1034:207

'Abd al-Samad narrated to us, 'Abd al-'Aziz ibn Muslim narrated to us, Yahya ibn 'Abd Allah al-Jabir narrated to us, he said: I prayed behind 'Isa, a freed slave of Hudhayfah, in al-Mada'in over a funeral, and he said five takbirs. Then he turned to us and said: "I did not err, nor did I forget, but I said the takbir as my master and the benefactor of my blessing, Hudhayfah ibn al-Yaman, said the takbir. He prayed over a funeral and said five takbirs." Then he turned to us and said: "I did not forget, nor did I err, but I said the takbir as the Messenger of Allah (may Allah bless him and grant him peace) said the takbir. He prayed over a funeral and said five takbirs."