Interpretation of a hadith

[Hamdi]

Someone told me a hadith and I was very impressed. It was about a group of people in the Judgement day who the Prophet SAW did'nt recognise as being from his ummah.

The Arabic text is here /don't know if the whole one/:

ليردن على ناس من أصحابي الحوض حتى إذا عرفتهم اختلجوا دونيز فأقول: أصحابي؟ فيقال: إنك لا تدري ما أحدثوا بعدك

Can anyone tell me to whom it refers?

[abulayl]

As long as i have read from various articles this hadith is mentioned against ahle bidah.