In the Hadith that Humran narrated, `Uthman washed between his fingers when he was
describing the Wudu' of the Prophet . The collectors of the Sunan recorded that
Laqit bin Sabrah said, "I said, `O Messenger of Allah! Tell me about Wudu'.' The
Messenger replied,
«أَسْبِغِ الْوُضُوءَ، وَخَلِّلْ بَيْنَ
الْأَصَابِعِ، وَبَالِغْ فِي الِاسْتِنْشَاقِ إِلَّا أَنْ تَكُونَ صَائِمًا»
(Perform Wudu' thoroughly, wash between the fingers and exaggerate in rinsing your
nose, unless you are fasting.)