On awakening from sleep no one should put his hands in a vessel before washing them
Sayyidina Abu Huraira (RA) narrated that the Prophet (SAW) said, "When one of you
awakes from sleep of the night, he must not dip his hand in the vessel till he has washed
it two or three times, for, he does not know where his hand was during the night."
[Ahmed8594, 9150, 10502, Bukhari 162, Abu Dawud 103 to 105, Muslim 278, Nisai 1]