It was narrated from 'Abdullah bin 'Amr that:
The Messenger of Allah passed by Sa'd when he was performing ablution, and he said: 'What is this extravagance?' He said: 'Can there be any extravagance in ablution?' He said: 'Yes, even if you are on the bank of a flowing river.'" (IT)
English reference (IT): Vol. 1, Book 1, Hadith 425 (IT)
Arabic reference (IT): Book 1, Hadith 460 (IT)