Narrated 'Abdullah bin 'Amr:
Once the Holy Prophet (Peace be upon him) remained behind us in a journey. He joined us while we were performing ablution for the prayer which was over-due. We were just passing wet hands over our feet
(and not washing them properly) so the Prophet addressed us in a loud voice and said twice or thrice: "Save your heels from the fire." (Bukhari Shareef)
"I must strive to reform myself and people of the entire world"
(selected by Muhammad Nasir Qadri)