Sunan an-Nasa'i 2980
It was narrated from Safiyyah bint Shaimah that a woman said:
I saw the Messenger of Allah hastening at the bottom of the valley and he said: "The river bed should not be crossed except with vigor." (Sahih)
Chpater 178. The Place Where One Should Walk
أَخْبَرَنَا قُتَيْبَةُ، قَالَ حَدَّثَنَا حَمَّادٌ، عَنْ بُدَيْلٍ، عَنِ الْمُغِيرَةِ بْنِ حَكِيمٍ، عَنْ صَفِيَّةَ بِنْتِ شَيْبَةَ، عَنِ امْرَأَةٍ، قَالَتْ رَأَيْتُ رَسُولَ اللَّهِ صلى الله عليه وسلم يَسْعَى فِي بَطْنِ الْمَسِيلِ وَيَقُولُ ‏
"‏ لاَ يُقْطَعُ الْوَادِي إِلاَّ شَدًّا ‏"‏ ‏.‏