Sunan Ibn Majah Book 1, Hadith 129

"The Messenger of Allah said: 'When anyone of oyu gets up from sleep and wants to perform ablution, he should not put his hand into the vessel he used for ablution until he has washed it, because he does not know where his hand spent the night or where he put it.'"

Previous Hadith

The Messenger of Allah said: "When anyone of you wakes up from sleep, he should not put his hand into the vessel until he has washed it."

Sunan Ibn Majah Book 1, Hadith 128
Next Hadith

"'Ali called for water, and he washed his hands before putting them in the vessel, then he said: 'This is what I saw the Messenger of Allah doing.'"

Sunan Ibn Majah Book 1, Hadith 130