Thawban bin Bujdud · The Book of Purification and its Sunnah

The Messenger of Allah said: "The key to prayer is purification, its opening is to say Allahu Akbar and its closing is to say As-salamu 'alaikum."

"I used to cover three vessels for the Messenger of Allah at night: A vessel (of water) for his ablution, a vessel for his tooth stick and a vessel for his drink."

The Prophet granted a concession to travelers: "If a traveler performed ablution and put on leather socks, then he performed a fresh ablution, he could wipe over the leather socks for three days and nights; the resident could do so for one day and one night."