Purification (Kitab Al-Taharah)
Dawud :: Book 1 : Hadith 384
Narrated A woman of the Banu AbdulAshhal:
She reported: I said Apostle of Allah, our road to the mosque has an unpleasant stench; what should we do when it is raining? He asked: Is there not a cleaner part after the filthy part of the road? She replied: Why not (there is one)! He said: It makes up for the other.