Sayyiduna Abu Umamah al-Bahili (may Allah be pleased with him) said: I said: O Messenger of Allah, will you recognise your Ummah on the Day of Resurrection? He (peace and blessings be upon him) said: "Yes." I said: Both those you have seen and those you have not seen? He (peace and blessings be upon him) said: "I will recognise them all, those I have seen and those I have not seen." I said: By what sign? He (peace and blessings be upon him) said: "Their faces, hands and feet will be bright and shining from the traces of ablution."
Hadith Referenceالمعجم الكبير للطبراني / باب الصاد / 7478