The Prophet(s.a.w) said, “Verily, whoever revives a tradition (sunnah) from among my traditions which has died after me, then he will have a reward similar to whoever acts upon it without taking anything away from their rewards; and whoever introduces an innovation with which Allah and His Messenger are not pleased, then he will have a sin similar to whoever acts upon it without taking anything away from the sins of the people.”
[Sunan At-Tirmidhi, Book of Knowledge, Number 2677, Hasan]