Sunan An-Nasai, Chapter: The Book of Purification

"I was behind Abu Hurairah when he performed Wudu for Salah. He washed his hand up to the armpit, and I said: 'O Abu Hurairah! What is this Wudu?' He said to me: 'O Banu Farrukh! You are here! If I had known that you were here I would not have performed Wudu like this. I heard my close friend (i.e., the Prophet) (saw) say: "The jewelry of the believer will reach as far as his Wudu reached." (Sahih)