My classmate and I talked about the old animes that we've watched, and we were reminiscing about the anime about a character that has a white haired man spirit. On his arm, there's something that's coming out of it. I remember that the ones that are coming out from his hand is his power. We forgot the title and the name of the lead character though.
It might be Shaman King. The anime ran from 2001-2002, which may qualify as old.
Asakura Yoh is a Shaman who uses the spirit of Amidamaru, a long dead samurai with white hair, during the Shaman Fights.
Sometimes, mostly early in the first season, Yoh and Amidamaru combine in such a way that their power comes out of Yoh's hands.