The impotence of Ablution

Abu Huraira reported: Verily Allah’s Messenger Sallallahu Alahih Wasallam said: My Cistern has its dimensions wider than the distance between Aila and Aden, and its water is whiter than ice and sweeter than the honey diluted with milk, and its cups are more numerous than the numbers of the 
stars. Verily I shall prevent the (faithless) people therefrom just as a man prevents the camels of the people from his fountain. They said: Messenger of Allah Sallallahu Alahih Wasallam will you recognise us on that day? He said: Yes, you will have distinctive marks which nobody among the peoples (except you) will have you would come to me with blazing forehead and bright hands and feet on account of the traces of ablution. 
Sahih Muslim Volume 1 , 581