Musnad Ahmad 30:1719

Husayn ibn Muhammad narrated to us, he said: Khalaf—meaning Ibn Khalifah—narrated to us, from Abu Malik al-Ashja‘i, from Abu Hazim, who said: I was behind Abu Hurayrah while he was performing ablution (wudu), and he was extending the ablution to his armpit. So I said: "O Abu Hurayrah, what is this ablution?" He said: "O son of Farrukh, you are here? Had I known you were here, I would not have performed this ablution in this manner. Indeed, I heard my beloved (the Prophet) say: 'The adornment of the believer reaches as far as the ablution reaches.'"