Imam Maalik مالك بن أنس بن مالك بن أبي عامر · The Book on Purification

Allah's Messenger said: "When a Muslim, or believer, performs Wudu', washing his face, every evil that he looked at with his eyes leaves with the water - or with the last drop of water, or an expression similar to that - and when he washes his hands, every evil he did with his hands leaves with the water - or with the last drop of water - until he becomes free of sin."

"Allah's Messenger wiped over his head with his hands, going over the front with them and the rear. He began with the front of his head until they went to the nape of his neck. Then he brought them back again to the place where he began. Then he washed his feet."

"A man asked Allah's Messenger 'O Messenger of Allah! We sail the seas, and we only carry a little water with us. If we use it for Wudu then we will go thirsty. So shall we perform Wudu from the (water of the) sea?' Allah's Messenger said: 'Its water is pure, and its dead are lawful.'"

"Kabshah bint Ka'b bin Malik - she was (married) with Ibn Abi Qatadah - narrated "That Abu Qatadah visited her, 'So I poured water for him to use for Wudu.' She said: 'A cat came to drink, so he lowered he container until it drank.' Kabshah said: 'So he saw me looking at it and said, "O my niece! Are you surprised at that?" So I said yes. He said: "Indeed Allah's Messenger said 'It is not impure, it is…

"I said to Umm Salamah: 'Indeed I am a woman with lengthy hems, and I walk in places of filth.' So she said: 'Allah's Messenger said: "It is purified by what comes after it."