Abu Hurairah used to say: "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 poured water on it two or three times, for none of you knows where his hand spent the night,'"  

قَالَ رَسُولُ اللَّهِ ﷺ إِذَا اسْتَيْقَظَ أَحَدُكُمْ مِنَ اللَّيْلِ فَلاَ يُدْخِلْ يَدَهُ فِي الإِنَاءِ حَتَّى يُفْرِغَ عَلَيْهَا مَرَّتَيْنِ أَوْ ثَلاَثًا فَإِنَّ أَحَدَكُمْ لاَ يَدْرِي فِيمَ بَاتَتْ يَدُهُ  

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."  

قَالَ رَسُولُ اللَّهِ ﷺ إِذَا اسْتَيْقَظَ أَحَدُكُمْ مِنْ نَوْمِهِ فَلاَ يُدْخِلْ يَدَهُ فِي الإِنَاءِ حَتَّى يَغْسِلَهَا  

"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.'" [(One of the narrators) Abu Ishaq said: "What is correct is that it is narrated from Jabir, from Abu Hurairah."]  

قَالَ رَسُولُ اللَّهِ ﷺ إِذَا قَامَ أَحَدُكُمْ مِنَ النَّوْمِ فَأَرَادَ أَنْ يَتَوَضَّأَ فَلاَ يُدْخِلْ يَدَهُ فِي وَضُوئِهِ حَتَّى يَغْسِلَهَا فَإِنَّهُ لاَ يَدْرِي أَيْنَ بَاتَتْ يَدُهُ وَلاَ عَلَى مَا وَضَعَهَا  

"'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.'"  

دَعَا عَلِيٌّ بِمَاءٍ فَغَسَلَ يَدَيْهِ قَبْلَ أَنْ يُدْخِلَهُمَا الإِنَاءَ ثُمَّ قَالَ هَكَذَا رَأَيْتُ رَسُولَ اللَّهِ ﷺ صَنَعَ