Ablutions (Wudu')
Bukhari :: Book 1 :: Volume 4 :: Hadith 167
Narrated 'Ubaid Ibn Juraij:
I asked 'Abdullah bin 'Umar, "O Abu 'Abdur-Rahman! I saw you doing four things which I never saw being done by anyone of you companions?" 'Abdullah bin 'Umar said, "What are those, O Ibn Juraij?" I said, "I never saw you touching any corner of the Ka'ba except these (two) facing south (Yemen) and I saw you wearing shoes made of tanned leather and dyeing your hair with Hinna; (a kind of dye). I also noticed that whenever you were in Mecca, the people assume l,hram on seeing the new moon crescent (1st of Dhul-Hijja) while you did not assume the Ihlal (Ihram)--(Ihram is also called Ihlal which means 'Loud calling' because a Muhrim has to recite Talbiya aloud when assuming the state of Ihram)--till the 8th of Dhul-Hijja (Day of Tarwiya). 'Abdullah replied, "Regarding the corners of Ka'ba, I never saw Allah's Apostle touching except those facing south (Yemen) and regarding the tanned leather shoes, no doubt I saw Allah's Apostle wearing non-hairy shoes and he used to perform ablution while wearing the shoes (i.e. wash his feet and then put on the shoes). So I love to wear similar shoes. And about the dyeing of hair with Hinna; no doubt I saw Allah's Apostle dyeing his hair with it and that is why I like to dye (my hair with it). Regarding Ihlal, I did not see Allah's Apostle assuming Ihlal till he set out for Hajj (on the 8th of Dhul-Hijja)."