Sunan Ibn Majah, Chapter: The Chapters of Purification and its Sunnah

"The Prophet (saw) went out to relieve himself and when he came back, I met him with a water skin and poured water for him. He washed his hands and his face, then he went to wash his forearms but his garment was too tight, so he brought his arms out from underneath his garment and washed them, then he wiped over his leather socks, then he led us in prayer." (Sahih)