It was narrated from Salim from his father that:
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." (JA)
English reference (JA): Vol. 1, Book 1, Hadith 394 (JA)
Arabic reference (JA): Book 1, Hadith 426 (JA)