"When any one of you wakes from sleep, let him not dip his hand in (the water he uses for) his Wudu' until he has washed it three times, for none of you knows where his hand spent the night." (Using translation from Nasāʾī 1)

عَنِ النَّبِيِّ ﷺ قَالَ «إِذَا اسْتَيْقَظَ أَحَدُكُمْ مِنْ مَنَامِهِ فَلَا يَغْمِسَنَّ يَدَهُ فِي إِنَائِهِ حَتَّى يَغْسِلَهَا ثَلَاثًا فَإِنَّهُ لَا يَدْرِي أَيْنَ بَاتَتْ يَدُهُ»